Patent Publication Number: US-2021170186-A1

Title: Plasma-type treatment device

Description:
TECHNICAL FIELD 
     The present invention relates to a plasma application therapeutic apparatus. 
     Priority is claimed on Japanese Patent Application No. 2017-215732, filed Nov. 8, 2017, the contents of which are incorporated herein by reference. 
     BACKGROUND ART 
     Conventionally, a plasma application therapeutic apparatus for medical use such as dental treatment has been known. The plasma application therapeutic apparatus cures the affected area by applying plasma or reactive gas to the affected area such as wounds. The reactive gas is generated by plasma in a plasma application therapeutic apparatus. For example, Patent Document 1 discloses a plasma jet application apparatus for implementing dental treatment. The plasma jet application apparatus is equipped with an application instrument having a plasma jet application means. The plasma jet application apparatus generates plasma and applies the generated plasma together with reactive species to a target object. The reactive species are generated by reaction of the plasma with the gas present within or around the plasma. 
     Patent Document 2 discloses a plasma application therapeutic apparatus that generates reactive gas (reactive species) inside an application instrument, and discharges the reactive gas from the nozzle of the application instrument to apply the reactive gas to an affected area of a patient. The reactive gas is, for example, active oxygen or active nitrogen. 
     DESCRIPTION OF PRIOR ART 
     Patent Document 
     
         
         Patent Document 1: Japanese Patent Granted Publication No. 5441066 
         Patent Document 2: Japanese Unexamined Patent Application Publication No. 2017-50267 
       
    
     DISCLOSURE OF INVENTION 
     Problems to be Solved by the Invention 
     As regards the conventional plasma application therapeutic apparatus, there is a room for improvement in usability for doctors, etc. In particular, the supply source of the plasma generating gas is usually an exchangeable cylinder or the like, and the plasma generating gas results in being wasted if the supply source is replaced while the plasma generating gas is still remaining in the supply source. In addition, the plasma application therapeutic apparatus itself seemingly operates normally even if the plasma generating gas in the supply source has been completely consumed, so that the plasma application therapeutic apparatus may be kept on being used unintentionally in spite of lack of the plasma generating gas in the supply source. This not only results in failure to obtain desired therapeutic effect, but also may pose a risk that a large amount of energy is caused to be wasted due to a large amount of electric power required to operate the plasma application therapeutic apparatus. This issue of energy wastage can also be a particularly acute problem when using portable power supplies. 
     Thus, there has been a risk that too early replacement of the supply source due to inability to accurately grasp the remaining amount of plasma generating gas may result in waste of the gas, while too late replacement could lead to undesirable consequences of inadequate therapeutic effect and waste of valuable electricity. 
     Further, in the field of plasma application therapy, there is a technique for deliberately controlling the reactive species produced by adding a small amount of a second gas to the main plasma generating gas. When this technique is used, it is necessary to install two types of cylinders on a plasma application therapeutic apparatus. In the case where different amounts of gases are used or the amount of a second gas is varied depending on the type of therapy, it is very difficult to accurately grasp the remaining amounts of the gases with conventional regulators that regulate pressure based on stored data. 
     The present invention has been made in view of the circumstances as described above, and the object of the invention is to improve the usability of a plasma application therapeutic apparatus by preventing the waste of plasma generating gas and electric power, and by ensuring the therapeutic effect. 
     Means to Solve the Problems 
     Embodiments proposed by the present invention in order to solve the above-mentioned problem are as enumerated below. 
     The plasma application therapeutic apparatus of the present invention includes: a plasma generating unit, a nozzle for discharging at least one of plasma generated by the plasma generating unit and a reactive gas generated by the plasma, a supply source for supplying a plasma generating gas to the plasma generating unit, an operation unit which is configured to be activated by a user to allow the supply source to supply a predetermined amount of the plasma generating gas to the plasma generating unit, and a reporting unit which is configured to report a remaining gas information in terms of remaining number of times allowed for the supply source to supply the plasma generating gas to the plasma generating unit, based on the plasma generating gas remaining in the supply source. 
     In this instance, the reporting unit reports the remaining number of times for supplying the plasma generating gas. Therefore, for example, the user can easily tell the timing of replacement of the supply source, and the usability of the plasma application therapeutic apparatus can be improved. 
     The plasma application therapeutic apparatus may further includes a calculation unit configured to calculate the remaining number of times, based on a remaining amount of the plasma generating gas in the supply source and a supply amount of the plasma generating gas per operation of the operation unit. 
     In this instance, the calculation calculates the remaining number of times for supplying the plasma generating gas, based on a remaining amount of the plasma generating gas in the supply source and a supply amount of the plasma generating gas per operation of the operation unit. This can improve the accuracy of the remaining number of times to be reported. 
     The plasma application therapeutic apparatus of the present invention includes: a plasma generating unit, a nozzle for discharging at least one of plasma generated by the plasma generating unit and a reactive gas generated by the plasma, a supply source for supplying a plasma generating gas to the plasma generating unit, and a reporting unit which is configured to report a remaining gas information in terms of remaining time allowed for the supply source to supply the plasma generating gas to the plasma generating unit, based on the plasma generating gas remaining in the supply source. 
     In this instance, the reporting unit reports the remaining time for supplying the plasma generating gas. Therefore, for example, the user can easily tell the timing of replacement of the supply source for the plasma generating gas, and the usability of the plasma application therapeutic apparatus can be improved. 
     The plasma application therapeutic apparatus may further includes a calculation unit configured to calculate the remaining time, based on a remaining amount of the plasma generating gas in the supply source and a supply amount of the plasma generating gas per unit time. 
     In this instance, the calculation unit calculates the remaining time for supplying the plasma generating gas, based on a remaining amount of the plasma generating gas in the supply source and a supply amount of the plasma generating gas per unit time. This can improve the accuracy of the remaining time to be reported. 
     The reporting unit may display the remaining gas information. 
     In this instance, the reporting unit displays the remaining gas information. Therefore, for example, the user can see the information on the remaining plasma generating gas, unlike the case in which the reporting unit announces the remaining gas information by voice. 
     The supply source may include two or more cylinders which are configured to respectively supply different plasma generating gases to the plasma generating unit. 
     In this instance, the supply source includes two or more cylinders, which respectively supply different plasma generating gases to the plasma generating unit. Therefore, it is possible to improve the accuracy of the remaining gas information of each cylinder by having the reporting unit report the remaining gas information on the remaining number of times or retaining time for allowing each cylinder to supply the plasma generating gas to the plasma generating unit. 
     Effect of the Invention 
     The present invention allows for improvement in the usability of a plasma application therapeutic apparatus by preventing the waste of plasma generating gas and electric power, and by ensuring the therapeutic effect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view showing a plasma application therapeutic apparatus according to one embodiment of the present invention. 
         FIG. 2  is a partial cross-sectional view showing an application instrument included in the plasma application therapeutic apparatus according to one embodiment of the present invention. 
         FIG. 3  is a cross-sectional view showing the application instrument of  FIG. 2  as viewed from the arrow direction of the x-x line of  FIG. 2 . 
         FIG. 4  is a cross-sectional view showing the application instrument of  FIG. 2  as viewed from the arrow direction of the y-y line of  FIG. 2 . 
         FIG. 5  is block diagram showing a schematic configuration of a plasma application therapeutic apparatus according to one embodiment of the present invention. 
         FIG. 6  is a schematic view showing an example of modification of the plasma application therapeutic apparatus of the present invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The plasma application therapeutic apparatus of the present invention is a plasma jet application apparatus or a reactive gas application apparatus. 
     The plasma jet application apparatus generates plasma. The plasma jet application apparatus generates plasma and applies the generated plasma together with reactive species to a target object. The reactive species are generated by reaction of the plasma with the gas present within or around the plasma. Examples of the reactive species include reactive oxygen species and reactive nitrogen species. Examples of the reactive oxygen species include hydroxyl radicals, singlet oxygen, ozone, hydrogen peroxide, and superoxide anion radicals. Examples of the reactive nitrogen species include nitric oxide, nitrogen dioxide, peroxynitrite, peroxynitrite, and dinitrogen trioxide. 
     The reactive gas application apparatus generates plasma. The reactive gas application apparatus applies the reactive gas containing the reactive species to a target object. The reactive species are generated by reaction of the plasma with the gas present within or around the plasma. 
     One embodiment of the plasma application therapeutic apparatus of the present invention is described below. 
     The plasma application therapeutic apparatus of the present embodiment is a reactive gas application apparatus. 
     As shown in  FIGS. 1 to 5 , the reactive gas application apparatus  100  of the present embodiment has an application instrument  10 , a detection unit  15 , a supply unit  20 , a gas conduit  30 , an electric wiring  40 , a supply source  70 , a reporting unit  80 , and a controller unit  90  (calculation unit). 
     The application instrument  10  discharges the reactive gas generated in the application instrument  10 . The supply unit  20  supplies electric power and plasma generating gas to the application instrument  10 . The supply unit  20  houses the supply source  70 . The supply source  70  contains the plasma generating gas. The supply unit  20  is connected to a power supply (not shown), such as a 100 V household power supply. In another one of the preferred embodiments of the present invention, the power supply is a portable power supply. The gas conduit  30  connects the application instrument  10  with the supply unit  20 . The electrical wiring  40  connects the application instrument  10  with the supply unit  20 . In the present embodiment, the gas conduit  30  and the electric wiring  40  are provided independently from each other, but the gas conduit  30  and the electric wiring  40  may be integrated. 
       FIG. 2  is a cross-sectional view (longitudinal section) showing a plane along the axis of the application instrument  10 . 
     As shown in  FIG. 2 , the application instrument  10  includes an elongated cowling  2 , a nozzle  1  protruding from the tip of the cowling  2 , and a plasma generating unit  12  provided in the cowling  2 . 
     The cowling  2  includes a cylindrical body  2   b  and a head  2   a  covering the tip of the body  2   b . The body  2   b  is not limited to that of a cylindrical shape, and may be of a polygonal tube shape such as a square tube shape, a hexagonal tube shape, an octagonal tube shape or the like. 
     The head  2   a  gradually narrows toward the tip thereof. That is, the head  2   a  in the present embodiment has a conical shape. The head  2   a  is not limited to that of a conical shape, and may be of a polygonal cone shape such as a quadrangular pyramid shape, a hexagonal pyramid shape, an octagonal pyramid shape or the like. 
     The head  2   a  has a fitting hole  2   c  at its tip. The fitting hole  2   c  is a hole for receiving the nozzle  1 . The nozzle  1  is detachably attached to the head  2   a . A first reactive gas flow path  7  extending in the tube axis O 1  direction is provided inside the head  2   a . The tube axis O 1  is a tube axis of the body  2   b.    
     The body  2   b  has an operation switch  9  (operation unit) on its outer peripheral surface. 
     As shown in  FIGS. 2 and 3 , the plasma generating unit  12  has a tubular dielectric  3  (dielectric), an inner electrode  4 , and an outer electrode  5 . 
     The tubular dielectric  3  is a cylindrical member extending in the tube axis O 1  direction. The tubular dielectric  3  has in its inside a gas flow path  6  extending in the tube axis O 1  direction. The gas flow path  6  communicates with a first reactive gas flow path  7 . The tube axis O 1  coincides with the tube axis of the tubular dielectric  3 . 
     In the tubular dielectric  3 , an inner electrode  4  is provided. The inner electrode  4  is a substantially columnar member extending in the tube axis O 1  direction. The inner electrode  4  is spaced apart from the inner surface of the tubular dielectric  3 . 
     On the outer peripheral surface of the tubular dielectric  3 , an outer electrode  5  extending along the inner electrode  4  is provided. The outer electrode  5  is an annular electrode that surrounds the outer peripheral surface of the tubular dielectric  3 . 
     As shown in  FIG. 3 , the tubular dielectric  3 , the inner electrode  4 , and the outer electrode  5  are positioned concentrically around the tube axis O 1 . 
     In the present embodiment, the outer peripheral surface of the inner electrode  4  and the inner peripheral surface of the outer electrode  5  face each other through the tubular dielectric  3 . 
     The nozzle  1  includes a base  1   b  fitted in the fitting hole  2   c , and a discharge tube  1   c  protruding from the base  1   b . The base  1   b  and the discharge tube c are integrated with each other. The nozzle  1  has in its inside a second reactive gas flow path  8 . The nozzle  1  has an outlet  1   a  at its tip end. The second reactive gas flow path  8  and the first reactive gas flow path  7  communicate with each other. 
     The material of the body  2   b  is not particularly limited, but is preferably an insulating material. Examples of the insulating material include thermoplastic resin, thermosetting resin, etc. Examples of the thermoplastic resin include polyethylene, polypropylene, polyvinyl chloride, polystyrene, acrylonitrile-butadiene-styrene resin (ABS resin), etc. Examples of the thermosetting resin include phenol resin, melamine resin, urea resin, epoxy resin, unsaturated polyester resin, silicon resin, etc. 
     The size of the body  2   b  is not particularly limited, and may be such a size that allows the body  2   b  to be easily grasped with fingers. 
     The material of the head  2   a  is not particularly limited, and may or may not be an insulating material. The material of the head  2   a  is preferably a material excellent in abrasion resistance and corrosion resistance. As an example of such a material excellent in abrasion resistance and corrosion resistance, a metal such as stainless steel can be listed. The materials of the head  2   a  and the body  2   b  may be the same or different. 
     The size of the head  2   a  can be decided in consideration of the use of the reactive gas application device  100  and the like. For example, when the reactive gas application apparatus  100  is an apparatus for an intraoral treatment, the size of the head  2   a  is preferably set to be such a size that allows the apparatus  100  to be inserted into an oral cavity. 
     As a material of the tubular dielectric  3 , a dielectric material used for a known plasma generator can be employed. Examples of the material of the tubular dielectric  3  include glass, ceramics, synthetic resins, and the like. The dielectric constant of the tubular dielectric  3  is preferably as low as possible. 
     The inner diameter R of the tubular dielectric  3  can be appropriately decided in consideration of the outer diameter d of the inner electrode  4 . The inner diameter R is set such that a distance s (described later) falls within a predetermined range. 
     The inner electrode  4  includes a shaft portion extending in the tube axis O 1  direction and a screw thread on the outer peripheral surface of the shaft portion. The shaft portion may be solid or hollow. Of these, a solid shaft portion is more preferable. The solid shaft portion allows easy processing and improves mechanical durability. The screw thread of the inner electrode  4  is a helical screw thread that circulates in the circumferential direction of the shaft portion. The shape of the inner electrode  4  is the same as that of a screw or a bolt. 
     The screw thread on the outer peripheral surface of the inner electrode  4  allows the electric field at the tip of the screw thread to be locally enhanced, thereby lowering the discharge inception voltage. Therefore, plasma can be generated and maintained with less electric power. 
     The outer diameter d of the inner electrode  4  can be appropriately decided in consideration of the actual use of the reactive gas application apparatus  10  (that is, the size of the application instrument  10 ) and the like. When the reactive gas application apparatus  100  is an apparatus for an intraoral treatment, the outer diameter d is preferably 0.5 mm to 20 mm, more preferably 1 mm to 10 mm. When the outer diameter d is not less than the above lower limit value, the inner electrode  4  can be easily manufactured. Further, the outer diameter d of not less than the above lower limit value increases the surface area of the inner electrode  4 , whereby plasma can be generated more efficiently, and healing and the like can be further promoted. When the outer diameter d is not more than the above upper limit value, plasma can be generated more efficiently and the healing and the like can be further promoted without excessively increasing the size of the application instrument  10 . 
     The height h of the screw thread of the inner electrode  4  can be appropriately decided in consideration of the outer diameter d of the inner electrode  4 . 
     The thread pitch p of the inner electrode  4  can be appropriately decided in consideration of the length and outer diameter d of the inner electrode  4 , and the like. 
     The material of the inner electrode  4  is not particularly limited as long as the material is electrically conductive, and metals used for electrodes of known plasma generating apparatuses can be used. Examples of the material of the inner electrode  4  include metals such as stainless steel, copper and tungsten, carbon, and the like. 
     The inner electrode  4  preferably has the same specification as any of the metric screw threads complying with JIS B 0205: 2001 (M2, M2.2, M2.5, M3, M3.5, etc.), the metric trapezoidal screw threads complying with JIS B 2016: 1987 (Tr8×1.5, Tr9×2. Tr9×1.5, etc.), the unified coarse screw threads complying with JIS B 0206: 1973 (No. 1-64 UNC, No. 2-56 UNC, No. 3-48 UNC, etc.), and the like. The inner electrode  4  having the same specification as those standardized products is advantageous in terms of cost. 
     The distances between the outer surface of the inner electrode  4  and the inner surface of the tubular dielectric  3  is preferably 0.05 mm to 5 mm, more preferably 0.1 nm to 1 mm. When the distance s is not less than the above lower limit value, a desired amount of plasma generating gas is allowed to flow easily. When the distance s is not more than the above upper limit value, plasma can be generated more efficiently and the temperature of the reactive gas can be lowered. 
     The material of the outer electrode  5  is not particularly limited as long as the material is electrically conductive, and metals used for electrodes of known plasma generating apparatuses can be used. Examples of the material of the outer electrode  5  include metals such as stainless steel, copper and tungsten, carbon, and the like. 
     The material of the nozzle  1  is not particularly limited, and may be an insulating material or a conductive material. The material of the nozzle  1  is preferably a material excellent in abrasion resistance and corrosion resistance. As an example of such a material excellent in abrasion resistance and corrosion resistance, a metal such as stainless steel can be listed. 
     The length (that is, the distance L 2 ) of the flow path in the discharge tube  1   c  in the nozzle  1  can be appropriately decided in consideration of the use of the reactive gas application apparatus  100  or the like. 
     The opening diameter of the outlet  1   a  is preferably, for example, 0.5 mm to 5 mm. When the opening diameter is not less than the above lower limit value, the pressure loss of the reactive gas can be suppressed. When the opening diameter is not more than the above upper limit value, the flow rate of the discharged reactive gas can be increased to promote healing and the like. 
     The discharge tube  1   c  is bent with respect to the tube axis O 1 . 
     The angle θ formed between the tube axis O 2  of the discharge tube  1   c  and the tube axis O 1  can be decided in consideration of the use of the reactive gas application apparatus  10  and the like. 
     The sum of the distance L 1  from the tip end Q 1  of the inner electrode  4  to the tip end Q 2  of the head  2   a  and the distance L 2  from the tip end Q 2  to the outlet  1   a  (that is, a distance from the inner electrode  4  to the outlet  1   a ) is appropriately decided in consideration of the size of the reactive gas application apparatus  100 , the temperature of a surface to which the reactive gas is applied (target surface), and the like. When the sum of the distance of L 1  and the distance L 2  is large, the temperature of the target surface can be lowered. When the sum of the distance of L 1  and the distance L 2  is small, the radical concentration of the reactive gas can be further increased, and the effects of cleaning, activation, healing, etc. on the target surface can be further enhanced. The tip end Q 2  is an intersection point between the tube axis O 1  and the tube axis O 2 . 
     As shown in  FIGS. 2, 4 and 5 , the detection unit  15  is provided in the application instrument  10 . As shown in  FIGS. 2 and 4 , the detection unit  15  detects an external force (impact force) received by the application instrument  10 . The detection unit  15  is closer to the plasma generating unit  12  than the nozzle  1 . When an external force is received by the application instrument  10 , the tubular dielectric  3  may be damaged by collision between the tubular dielectric  3  provided in the plasma generating unit  12  and the inner electrode  4  disposed therein. Therefore, it is preferable that the detection unit  15  is provided at a position closer to the plasma generating unit  12  than the nozzle  1  to detect the external force received by the plasma generating unit  12 . This makes it possible to determine whether or not the tubular dielectric material  3  is damaged. 
     Here, the phrase “closer to the plasma generating unit  12  than the nozzle  1 ” means that the distance A from the tubular dielectric  3 -side end of the detector unit  15  to the tip of the tubular dielectric  3  with respect to the nozzle  1  and the plasma generating unit  12 , which are separated along the tube axis O 1 , is shorter than the distance B from the nozzle  1 -side end of the detector unit  15  to the root of the nozzle  1  (the boundary between the nozzle  1  and the cowling  2 ) (i.e., the ratio of distance B/distance A is less than 1). The distance A being 0 encompasses not only the case in which the position of the tubular dielectric  3 -side end of the detection unit  15  and the position of the tip of the tubular dielectric  3  of the detection unit  15  coincide when viewed from the front of the detection unit  15  (i.e., viewed from the detection unit  15 &#39;s surface opposite to the tubular axis O 1 ), but also the case in which the detection unit  15  overlaps with the tubular dielectric  3 . 
     As is evident front the above, damage to the tubular dielectric  3  is particularly likely to occur at a point where the tubular dielectric  3  and the internal electrode  4  are opposed to each other. In addition, as shown in  FIG. 2 , when the internal electrode  4  is shorter than the tubular dielectric  3  and the tip of the internal electrode  4  is opposed to the inner surface of the tubular dielectric  3 , damage to the tubular dielectric  3  is particularly likely to occur where the tip of the internal electrode  4  is opposed to the inner surface of the tubular dielectric  3 . Therefore, it is more preferable that the detection unit  15  is provided at a position where the tubular dielectric  3  is opposed to the internal electrode  4 , especially where the detection unit  15  can surely detect an external force received at a position where the tip of the internal electrode  4  is opposed to the inner surface of the tubular dielectric  3 . From this point of view, it is preferable for the detection unit  15  to be located at a position that overlaps the tubular dielectric  3  when the detection portion  15  is viewed from its front (i.e., the detection unit  15 &#39;s surface opposite the tube axis O 1 ), and it is more preferable for the detection unit  15  to be located at a position that overlaps the tip of the inner electrode  4 . 
     In addition, it is necessary to place the detection unit  15  in the application instrument  10  at a position where it receives an impact equal to or greater than that received by the tubular dielectric  3 . For example, it is preferable to place the detection unit  15  in a member that is continuously connected to the member that is in contact with the tubular dielectric  3  without the use of rubber such as an O-ring. Further, when the tubular dielectric  3  is disposed within the body  2   b  of the application instrument  10 , separated from the body  2   b  through an O-ring or the like, it is preferable that the loss tangent of the member provided with the detection unit  15 , which is positioned outside the member holding the tubular dielectric material  3 , is equal to or less than the loss tangent of the material (poor shock absorption material) with which the tubular dielectric material  3  is proximate. Furthermore, it is preferable to position the detection unit  15  at a position where the impact received by the application instrument  10  can be directly detected. Specifically, a material with a velocity of elastic wave propagation inside the material of at least 3000 m/sec is placed in the outermost layer of the body  2   b  of the application instrument  10 , and the detection unit  15  is placed in contact with such a material. As the material with a velocity of elastic wave propagation inside the material of at least 3000 m/sec, metallic materials, etc. can be used. 
     The detection unit  15  is disposed in the recess  16 . The recess  16  is formed on the inner periphery of the body  2   b . Supposing that the direction orthogonal to the tube axis O 1  is in the radial direction, the detection unit  15  is located outside the tube dielectric  3  in the radial direction. The detection unit  15  is shaped in the form of a tube that extends in the direction of the tube axis O 1 . The tubular shape of the detection unit  15  allows the detection unit  15  to be placed in a narrow area within the application instrument  10 . However, the detection unit  15  is not limited to that of a tubular shape, but can be of any shape as long as it has the function as described below. 
     In the context of the present specification, the term “external force” refers to the force that the application instrument  10  receives from the outside due to impact, etc. More specifically, this term refers to an impact force received by the application instrument having fallen on a floor and the like; an impact force received by the application instrument having hit a wall and the like due to pendulum motion of the application instrument dangling by wiring connected thereto: an impact force caused by a heavy object having fallen on the application instrument; and the like. 
     The detection unit  15  changes its color when an external force is applied to the application instrument  10 . In the present embodiment, the color of the detection  15  differs between before and after the detection unit  15  receives an external force reaching or exceeding a threshold level. The color of the detection unit  15  remains the same without returning to its original color after the detection unit  15  receives an external force reaching or exceeding the threshold level. 
     The detection unit  15  is visible from the outside of the application instrument  10 . The cowling  2  has an observation window  17 . The observation window  17  is located outside of the detection unit  15  (recess  16 ) as viewed in its radial direction. The detection unit  15  is visible from the outside of the application instrument  10  through the observation window  17 . 
     The supply unit  20 , as shown in  FIG. 1 , supplies electricity and plasma generating gas to the application instrument  10 . The supply unit  20  it capable of adjusting the voltage and frequency applied between the inner electrode  4  and the outer electrode  5 . The supply unit  20  has a housing  21  that houses the supply source  70 . The housing  21  accommodates the supply source  70  in a detachable manner. Thus, when the gas in the supply source  70  accommodated in the housing  21  runs out, the supply source  70  for plasma generating gas can be replaced. 
     The supply source  70  supplies the plasma generating gas to the plasma generating unit  12 . The supply source  70  is a pressure-resistant vessel filled with the plasma generating gas. As shown in  FIG. 5 , the supply source  70  is detachably attached to the pipe  75  disposed in the housing  21 . The pipe  75  connects the supply source  70  with the gas conduit  30 . For example, a replaceable cylinder (gas cylinder) can be used as the supply source  70 . 
     A solenoid valve  71 , a pressure regulator  73 , a flow rate controller  74 , and a pressure sensor  72  (residual volume sensor) are attached to the pipe  75 . 
     When the solenoid valve  71  is opened, the plasma generating gas is supplied from the supply source  70  to the application instrument  10  through pipe  75  and gas conduit  30 . In the example shown in the drawing, the solenoid valve  71  is not configured to enable adjustment of the valve opening degree, but is configured to enable only switch between opening and closing. However, the solenoid valve  71  may also be configured to enable adjustment of the valve opening degree. 
     The pressure regulator  73  is positioned between the solenoid valve  71  and the supply source  70 . The pressure regulator  73  lowers the pressure of the plasma generating gas from the supply source  70  to the solenoid valve  71  (i.e., the pressure regulator  73  reduces the pressure of the plasma generating gas). 
     The flow rate controller  74  is disposed between the solenoid valve  71  and the gas conduit  30 . The flow rate controller  74  adjusts the flow rate (supply rate per unit time) of the plasma generating gas having passed through the solenoid valve  71 . For example, the flow rate controller  74  adjusts the flow rate of the plasma generating gas to 3 L/min. 
     The pressure sensor  72  measures the remaining amount of plasma generating gas V 1  in the supply source  70 . The pressure sensor  72  measures the remaining amount V 1  in terms of the pressure (remaining pressure) in the supply source  70 . The pressure sensor  72  measures the pressure (upstream pressure) of the plasma generating gas passing between the pressure regulator  73  and the supply source  70  (positioned upstream of the pressure regulator  73 ) as the pressure of the supply source  70 . As the pressure sensor  72 , for example, the AP-V80 series (e.g., AP-15S) manufactured by Keyence Corporation can be employed. 
     The remaining amount V 1  (volume) at the supply source  70  is calculated from the remaining pressure measured by the pressure sensor  72  and the capacity (internal volume) of the supply source  70 . 
     Assuming that supply sources  70  of various capacities are used as the supply source  70 , for example, the capacity for the calculation may be set by selecting the capacity of the actual supply source  70  on the system screen of the input section not shown. 
     Alternatively, when supply sources  70  of the same capacity are used as the supply source  70 , the capacity may be input into and stored in the controller unit  90  in advance. 
     A joint  76  is provided at the end of pipe  75  on the supply source  70 -side. The supply source  70  is detachably attached to the joint  76 . The attachment or detachment of the supply source  70  to or from the joint  76  allows for replacement of the supply source  70  for the plasma generating gas while leaving the solenoid valve  71 , the pressure regulator  73 , the flow rate controller  74 , and the pressure sensor  72  (hereinafter collectively referred to as “solenoid valve  71 , etc.”) fixed to the housing  21 . In this case, a common solenoid valve  71 , etc. can be used for both the old and new supply sources  70  before and after the replacement. In addition, the solenoid valve  71 . etc. may be integrally fixed to the supply source  70  so as to detachable from the housing  21  together with the supply source  70 . 
     The supply source  70  may include two or more cylinders, which respectively supply different plasma generating gases to the plasma generating unit  12 . In this instance, it is possible to improve the accuracy of the remaining gas information of each cylinder by having the reporting unit  80  report the remaining gas information on the remaining number of times or retaining time for allowing each cylinder to supply the plasma generating gas to the plasma generating unit  12 . 
     When the supply source  70  includes two or more cylinders, the reactive gas application apparatus  100  may have reporting units respectively corresponding to the cylinders. In other words, the reactive gas application apparatus  100  may be provided with the same number of reporting units  80  as the number of cylinders. 
     As shown in  FIG. 1 , the gas conduit  30  forms a path for supplying the plasma generating gas from the supply unit  20  to the application instrument  10 . The gas conduit  30  is connected to the rear end of the tubular dielectric  3  of the application instrument  10 . The material of the gas conduit  30  is not particularly limited, and a material used for known gas pipes can be used. Concerning a material of the gas conduit  30 , a resin pipe, a rubber tube and the like can be listed as examples, and a material having flexibility is preferable. 
     The electrical wiring  40  is a wiring for supplying electricity from the power supply unit  20  to the application instrument  10 . The electric wiring  40  is connected to the inner electrode  4 , the outer electrode  5  and the operation switch  9  of the application instrument  10 . The material of the electric wiring  40  is not particularly limited, and a material used for a known electric wiring can be employed. As examples of the material of the electric wiring  40 , a metal lead wire covered with an insulating material and the like can be mentioned. 
     The controller unit  90  as shown in  FIG. 5  is composed of an information processing unit. In other words, the controller unit  90  is equipped with a CPU (central processing unit), a memory and an auxiliary storage device, which are connected by buses. The controller unit  90  operates by executing a program. The controller unit  90  may, for example, be built into the supply unit  20 . The controller unit  90  controls the application instrument  10 , the supply unit  20 , and the reporting unit  80 . 
     An operation switch  9  for the application instrument  10  is electrically connected to the controller unit  90 . When the operation switch  9  is turned on, an electrical signal is sent from the operation switch  9  to the controller unit  90 . When the controller unit  90  receives the electrical signal, the controller unit  90  activates the solenoid valve  71  and the flow rate controller  74 , and applies a voltage between the inner electrode  4  and the outer electrode  5 . 
     In the present embodiment, when the operation switch  9  is a push button and the user pushes the operation switch  9  once (i.e., when the user has turned on the operation switch  9 ), the controller unit  90  receives the electrical signal described above. Then, the controller unit  90  opens the solenoid valve  71  for a predetermined period of time to allow the flow rate controller  74  to adjust the flow rate of the plasma generating gas having passed through the solenoid valve  71 , and applies a voltage between the inner electrode  4  and the outer electrode  5  for a predetermined period of time. As a result, a predetermined amount of plasma generating gas is supplied to the plasma generating unit  12  from the supply source  70 , and the reactive gas is continuously discharged from the nozzle  1  for a predetermined period of time (e.g., several seconds to several tens of seconds, or 30 seconds in the present embodiment). 
     That is, in the present embodiment, the amount of reactive gas discharged per one push of the operation switch  9  by the user is fixed. Such an operation for discharging a predetermined amount of reactive gas is defined as unit operation. In the present embodiment, the unit operation is a single push of the operation switch  9  by the user. The discharge amount of reactive gas per unit operation (the amount of plasma generating gas supplied from the supply source  70  to the plasma generating unit  12  per unit operation) may be a fixed value set beforehand, or may be a variable value that can be set by input through an operation panel not shown, etc. 
     The controller unit  90  calculates at least one of the remaining number of times N and the remaining time T for supplying the plasma generating gas to provide the remaining gas information. In the present embodiment, as the remaining gas information which may either be the remaining number of times N or the remaining time T, the controller unit  90  calculates only the remaining number of times N. 
     The remaining number of times N is the number of remaining unit operations allowed for the supply source  70  to supply the plasma generating gas to the plasma generating unit  12 , based on the amount of the plasma generating gas remaining in the supply source  70 . The remaining time T is the time allowed for the supply source  70  to supply the plasma generating gas to the plasma generating unit  12 , based on the amount of the plasma generating gas remaining in the supply source  70 . Further, it is necessary to stop the use of the supply source  70  while leaving some internal pressure (gas pressure) in the supply source  70  in order to avoid a decrease in workability for re-filling the plasma generating gas into the supply source  70 . Therefore, the remaining number of times N is set to be less than the remaining number of times supposed to be allowed for the supply source  70  to supply the plasma generating gas until the gas is completely consumed to generate plasma. Likewise, the remaining time T is set to be shorter than the remaining time supposed to be allowed for the supply source  70  to supply the plasma generating gas until the gas is completely consumed to generate plasma. 
     Both the remaining number of times N and the remaining time T can be calculated from the remaining amount V 1  of the plasma generating gas in the supply source  70 . 
     The remaining number of times N can be calculated, based on the remaining amount V 1  and the supply amount V 2  of the plasma generating gas per unit operation triggered by the operation switch  9  (that is, N=V 1 /V 2 ). Specifically, the remaining number of times N is calculated by calculating the average value V 2  of the amount of the plasma generating gas used (supply amount) for the latest several runs of operation, and dividing the average value V 2  by the remaining amount V 1  of the plasma generating gas. 
     The remaining time T can be calculated, based on the remaining amount V 1  and the supply amount V 3  of the plasma generating gas supplied from the supply source  70  to the plasma generating unit  12  per unit time (that is, T=V 1 /V 3 ). 
     The reporting unit  80  reports at least one of the remaining number of times N and the remaining time T. In the present embodiment, the reporting unit  80  displays the remaining number of times N. The reporting unit  80  displays the remaining number of times N as a number calculated by the controller unit  90 . For example, the reporting unit  80  may be a display device capable of displaying arbitrary numbers, or a mechanical counter. 
     In the example shown in the drawing, the reporting unit  80  is integrally provided with the housing  21  on the outer surface thereof, but may be provided independently of the supply unit  20 . Further, the reporting unit  80  may display the remaining number of times N in a form other than numbers. For example, the reporting unit  80  may have a configuration that provides an analog display formed by a dial and a hand. Furthermore, for example, the reporting unit  80  may report the remaining number of times N by means of color display or lighting. In this instance, for example, it is conceivable to divide the remaining number of times N into multiple stages in advance. Specifically, for example, the display color may be changed at the respective stages (e.g., blue when the remaining number of times N is sufficiently high, yellow when the remaining number of times N is low, red when the remaining number of times N is very low, etc.). Alternatively, lighting and blinking may be switched at respective stages (e.g., constant lighting when the remaining number of times N is sufficiently high, long blinking when the remaining number of times N is low, short blinking when the remaining number of times N is very low, etc.). 
     Further, the reporting unit  80  may notify the remaining number N by voice. In this instance, for example, the reporting unit  80  may be a speaker. Further, in this instance, the remaining number of times N may be readout as numbers. Alternatively, the reporting unit  80  may be configured to set off an alarm sound or the like when the remaining number of times N reaches or goes below a predetermined threshold or becomes 0. It is also possible to combine the above-mentioned display of the remaining number of times N by means of numbers, etc. with the above-mentioned notification of the remaining number of times N by means of voice or alarm sounds, etc. Such a combination enables the user to recognize the remaining number of times N more quickly. 
     As in the present embodiment, when a predetermined amount of the plasma generating gas is supplied from the supply source  70  to the plasma generating unit  12  when the user turns on the operation switch  9 , it is more convenient for the user to have the reporting unit report the remaining number of times N than the remaining time T. Unlike the present embodiment, for example, in the case of a configuration in which the plasma generating gas is continuously supplied to the plasma generating unit  12  while the operation switch  9  is being pressed down by the user, it is more convenient for the user to have the reporting unit report the remaining time T as in the case of the reactive gas application apparatus  100 B of the modified example shown in  FIG. 6  than the remaining number of times N. Even when the user knows the remaining gas pressure of the gas for plasma generation in the supply source  70 , the remaining time T is reported as long as the user does not know the remaining number of times N. 
     When the controller unit  90  is connectable to a telecommunication line, the controller unit  90  may be configured to place an order for a new supply source  70  through the telecommunication line when the remaining number of times N or the remaining time T reaches or goes below a predetermined threshold. 
     Next, a method of using the reactive gas application apparatus W will be described. 
     A user, such as a doctor, holds and moves the application instrument  10 , and points the nozzle  1  at a target object to be described later. In this state, the operation switch  9  is pushed to supply electricity and the plasma generating gas to the application instrument  10  from the supply source  70 . 
     The plasma generating gas supplied to the application instrument  10  is allowed to flow into the hollow portion of the tubular dielectric  3  from the rear end of the tubular dielectric  3 . The plasma generating gas is ionized at a position where the inner electrode  4  and the outer electrode  5  face each other, and turned into plasma. 
     In the present embodiment, the inner electrode  4  and the outer electrode  5  face each other in a direction orthogonal to the flowing direction of the plasma generating gas. Plasma generated at a position where the outer peripheral surface of the inner electrode  4  and the inner peripheral surface of the outer electrode  5  face each other is allowed to pass through the gas flow path  6 , the first reactive gas flow path  7 , and the second reactive gas flow path  8  in this order. In this process, the plasma flows while changing the gas composition, and becomes a reactive gas containing reactive species such as radicals. 
     The generated reactive gas is discharged from the outlet  1   a . The discharged reactive gas further activates a part of the gas in the vicinity of the outlet  1   a  into reactive species. The reactive gas containing these reactive species is applied to a target object. 
     Examples of the target object include cells, living tissues, and whole bodies of organisms. 
     Examples of the living tissue include various organs such as internal organs, epithelial tissues covering the body surface and the inner surfaces of the body cavity, periodontal tissues such as gums, alveolar bone, periodontal ligament and cementum, teeth, bones and the like. 
     The whole bodies of organisms may be any of mammals such as humans, dogs, cats, pigs and the like; birds; fishes and the like. 
     Examples of the plasma generating gas include noble gases such as helium, neon, argon and krypton: nitrogen; and the like. With respect to these gases, a single type thereof may be used individually or two or more types thereof may be used in combination. 
     The plasma generating gas preferably contains nitrogen gas as a main component. Here, the nitrogen gas being contained as a main component means that the amount of the nitrogen gas contained in the plasma generating gas is more than 50% by volume. More specifically, the amount of the nitrogen gas contained in the plasma generating gas is preferably more than 50% by volume, more preferably 70% by volume or more, still more preferably 90% by volume to 100% by volume. The gas component other than nitrogen in the plasma generating gas is not particularly limited, and examples thereof include oxygen and a noble gas. 
     When the reactive gas application apparatus  100  is an apparatus for an intraoral treatment, the plasma generating gas to be introduced into the tubular dielectric  3  preferably has an oxygen concentration of 1% by volume or less. When the oxygen concentration is not more than the upper limit value, generation of ozone can be suppressed. 
     The flow rate of the plasma generating gas introduced into the tubular dielectric  3  is preferably 1 L/min to 10 L/min. 
     When the flow rate of the plasma generating gas introduced into the tubular dielectric  3  is not less than the above lower limit value, it becomes easy to suppress the temperature rise of a target surface of the target object. The flow rate is not more than the above upper limit value, the cleaning, activation or healing of the target object can be further promoted. 
     The alternating voltage applied between the inner electrode  4  and the outer electrode  5  is preferably 5 kVpp or more and 20 kVpp or less. Here, the unit “Vpp (peak-to-peak voltage)” representing the alternating voltage means a potential difference between the highest value and the lowest value of the alternating voltage waveform. 
     When the applied alternating voltage is not more than the above upper limit value, the temperature of the generated plasma can be kept low. When the applied alternating voltage is not less than the above lower limit value, plasma can be generated more efficiently. 
     The frequency of the alternating voltage applied between the inner electrode  4  and the outer electrode  5  is preferably 0.5 kHz or more and less than 20 kHz, more preferably 1 kHz or more and less than 15 kHz, even more preferably 2 kHz or more and less than 10 kHz, particularly preferably 3 kHz or more and less than 9 kHz, and most preferably 4 kHz or more and less than 8 kHz. 
     With the frequency of the alternating voltage set to less than the above upper limit value, the temperature of the generated plasma can be suppressed low. With the frequency of the alternating voltage set to equal or exceed the above lower limit value, plasma can be generated more efficiently. 
     The temperature of the reactive gas discharged from the outlet  1   a  of the nozzle  1  is preferably 50° C. or less, more preferably 45° C. or less, and even more preferably 40° C. or less. 
     When the temperature of the reactive gas discharged from the outlet  1   a  of the nozzle  1  is not more than the upper limit value, the temperature of the target surface can be easily adjusted to 40° C. or less. By keeping the temperature of the target surface at 40° C. or less, stimulus to the target surface can be reduced even when the target surface is an affected part. 
     The lower limit value of the temperature of the reactive gas discharged from the outlet  1   a  of the nozzle is not particularly limited, and is, for example, 10° C. or more. 
     The temperature of the reactive gas is a temperature value of the reactive gas at the outlet  1   a  measured by a thermocouple. 
     The distance (application distance) from the outlet  1   a  to the target surface is preferably, for example, 0.01 mm to 10 mm. When the application distance is not less than the above lower limit value, the temperature of the target surface can be lowered, and the stimulus to the target surface can be further reduced. When the application distance is not more than the above upper limit value, the effect of healing and the like can be further enhanced. 
     The temperature of the target surface positioned at a distance of t mm or more and 10 mm or less from the outlet  1   a  is preferably 40° C. or less. By setting the temperature of the target surface to 40° C. or less, stimulus to the target surface can be reduced. The lower limit value of the temperature of the target surface is not particularly limited, and is, for example, 10° C. or more. 
     The temperature of the target surface is adjusted by controlling the alternating voltage applied between the inner electrode  4  and the outer electrode  5 , the discharge amount of the reactive gas, the distance from the tip end Q 1  of the inner electrode  4  to the outlet  1   a , and the like, some or all of which are controlled in combination. 
     The temperature of the target surface can be measured by a thermocouple. 
     Examples of the reactive species (radicals etc.) contained in the reactive gas include hydroxyl radicals, singlet oxygen, ozone, hydrogen peroxide, superoxide anion radicals, nitric oxide, nitrogen dioxide, peroxynitrite, dinitrogen trioxide and the like. The type of the reactive species contained in the reactive gas can be further controlled by, for example, the type of the plasma generating gas. 
     The hydroxyl radical concentration of the reactive gas (radical concentration) is preferably 0.1 mol/l to 300 mol/L. When the radical concentration is not less than the lower limit value, the promotion of cleaning, activation or healing of a target object selected from a cell, a living tissue and a whole body of an organism is facilitated. When the radical concentration is not more than the upper limit value, stimulus to the target surface can be reduced. 
     The radical concentration can be measured, for example, by the following method. 
     A reactive gas is applied to 0.2 mL of a 0.2 mol/L solution of DMPO (5,5-dimethyl-1-pyrroline-N-oxide) for 30 seconds. Here, the distance from the outlet  1   a  to a liquid surface of the solution is set to 5.0 nm. With respect to the solution to which the reactive gas has been applied, a hydroxyl radical concentration is measured by electron spin resonance (ESR) method. 
     The singlet oxygen concentration of the reactive gas is preferably 0.1 mol/L to 300 μmol/L. When the singlet oxygen concentration is not less than the lower limit value, the promotion of cleaning, activation or healing of a target object such as a cell, a living tissue or a whole body of an organism is facilitated. When the singlet oxygen concentration is not more than the upper limit value, stimulus to the target surface can be reduced. 
     The singlet oxygen concentration can be measured, for example, by the following method. 
     A reactive gas is applied to 0.4 mL of a 0.1 mol/solution of TPC (2,2,5,5-tetramethyl-3-pyrroline-3-carboxamide) for 30 seconds. Here, the distance from the outlet  1   a  to a liquid surface of the solution is set to 5.0 mm. With respect to the solution to which the reactive gas has been applied, a singlet oxygen concentration is measured by electron spin resonance (ESR) method. 
     The flow rate of the reactive gas discharged from the outlet  1   a  is preferably 1 L/min to 10 L/min. 
     When the flow rate of the reactive gas discharged from the outlet  1   a  is not less than the above lower limit value, the effect of the reactive gas acting on the target surface can be sufficiently enhanced. When the flow rate of the reactive gas discharged from the outlet  1   a  is less than the above upper limit value, excessive increase in the temperature of the reactive gas at the target surface can be prevented. In addition, when the target surface is wet, rapid drying of the target surface can be prevented. Furthermore, when the target surface is an affected part of a patient, stimulus inflicted on the patient can be further suppressed. 
     In the reactive gas application apparatus  100 , the flow rate of the reactive gas discharged from the outlet  1   a  can be adjusted by the supply amount of the plasma generating gas to the tubular dielectric  3 . 
     The reactive gas generated by the reactive gas application apparatus  100  has an effect of promoting healing of trauma and other abnormalities. The application of the reactive gas to a cell, a living tissue or a whole body of an organism can promote cleaning, activation or healing of the target part to which the reactive gas is applied. 
     For applying a reactive gas for the purpose of promoting healing of trauma and other abnormalities, there is no particular limitation with regard to the interval, repetition number and duration of the application. For example, when a reactive gas is applied to an affected part at a dose of 1 L/min to 5.0 L/min, the application conditions preferred for promoting healing are as follows: 1 to 5 times per day, 10 seconds to 10 minutes for each repetition, and 1 to 30 days as total duration of treatment. 
     The reactive gas application apparatus  100  of the present embodiment is useful especially as an oral cavity treatment apparatus or a dental treatment apparatus. Further, the reactive gas application apparatus  100  of the present embodiment is also suitable as an animal treatment apparatus. 
     According to the reactive gas application apparatus  100  of the present embodiment as described above, the reporting unit  80  reports the remaining number of times N for supplying the plasma generating gas. Therefore, for example, the user can easily tell the timing of replacement of the supply source  70 , and the usability of the plasma application therapeutic apparatus  100  can be improved. The supply source  70  is replaceable, and the plasma generating gas results in being wasted if the supply source  70  is replaced while the plasma generating gas is still remaining in the supply source  70 . According to the reactive gas application apparatus  100  of the present embodiment, the user can easily tell the timing of replacing the supply source  70 , so that the supply source  70  can be replaced after the plasma generating gas has been completely consumed. 
     The reporting unit  80  displays the remaining number of times N. Therefore, for example, the user can see the information on the remaining number of times N for supplying plasma generating gas, unlike the case in which the reporting unit  80  announces the remaining number of times N by voice. 
     The controller unit  90  calculates the remaining number of times N for supplying the plasma generating gas, based on the remaining amount (V 1 ) of the plasma generating gas in the supply source  70  and the supply amount (V 2 ) of the plasma generating gas per unit operation triggered by the operation switch  9 . Therefore, the accuracy of the remaining number of times N to be reported can be increased. 
     In addition, the reactive gas application apparatus  100  of the present embodiment can also detect the leakage of the plasma generating gas. For example, the leakage of the plasma generating gas is detected by checking the pressure difference of the plasma generating gas at the supply source  70  from the pressure before use, the pressure after use, and the record of use on that day. 
     Other Embodiments 
     The present invention is not limited to the above embodiment. 
     The detection unit  15  may be omitted. 
     The operation switch  9  may be different from the above embodiment. For example, the supply unit  20  may be provided with a foot pedal, instead of providing an operation switch  9  in the application instrument  10 . In this instance, a foot pedal can be used as an operation unit and, for example, it is possible to employ a configuration in which the plasma generating gas is supplied to the plasma generating unit  12  from the supply source  70  when the user steps on the foot pedal. 
     The controller unit  90  may be configured to calculate the remaining number of times N without relying on the remaining amount (V 1 ) of the plasma generating gas in the supply source  70  and the supply amount (V 2 ) of the plasma generating gas per unit operation triggered by the operation switch  9 . For example, the controller unit  90  may be configured to calculate the remaining number of times N by previously storing the input number of times N 1  for the new supply source  70 , and storing the input cumulative number of times N 2  (cumulative discharge times) of turning on the operation switch  9  after starting to use the new supply source  70  (that is. N=N 1 −N 2 ). 
     The method as described above which measures the remaining amount V 1  of the plasma generating gas in the supply source  70  using a pressure sensor  72  (i.e. method of calculating the remaining amount by monitoring the primary pressure with the pressure sensor  72 ) is preferable because it allows for more accurate determination of the remaining amount V 1  in the supply source  70 . 
     However, the method of measuring the remaining amount V 1  is not limited to this method, and the remaining amount V 1  may be calculated without using the pressure sensor  72 . For example, the controller unit  90  may count the number of times the unit operation has been performed and calculate the remaining amount V 1  by subtraction from the initial gas amount. Further, the remaining amount V 1  may be calculated by calculating the amount of the already used plasma generating gas by multiplying the set value of the flow rate controller  74  by an operation time, and subtracting this amount of the used gas from the amount of the plasma generating gas in a new supply source  70 . These calculations can be performed, for example, by the controller unit  90 . Also, in this instance, the pipe  75  can be simplified by dispensing with the pressure sensor  72 , for example by directly connecting the supply source  70  to the pressure regulator  73  (regulator). As a result, for example, the efficiency in operation for replacement of the supply source  70  can be improved. In addition, a metal pipe may be employed as the pipe  75  to improve the pressure resistance of the pipe  75 . 
     The shape of the inner electrode  4  of the present embodiment described above is a screw shape. However, the shape of the inner electrode is not limited as long as plasma can be generated between the inner electrode and the outer electrode. 
     The inner electrode may or may not have concavities and convexities on its surface. However, the inner electrode preferably has concavities and convexities on the outer peripheral surface. 
     For example, the shape of the inner electrode may be a coil shape, or may be a rod shape or a cylindrical shape in which a plurality of protrusions, holes, and through holes are formed on the outer peripheral surface. The cross-sectional shape of the inner electrode is not particularly limited, and may be, for example, a circular shape such as a true circle or an ellipse, or a polygonal shape such as a square or a hexagon. 
     The features of the embodiments described above can be appropriately replaced by known equivalents as long as such replacement does not deviate from the essence of the present invention, and the modifications described above may be combined as appropriate. 
     DESCRIPTION OF THE REFERENCE SIGNS 
     
         
           1  Nozzle 
           9  Operation switch 
           10  Application instrument 
           12  Plasma generating unit 
           15  Detection unit 
           70  Supply source 
           80  Detection unit 
           90  Controller unit (calculation unit) 
           100 , 100 B Reactive gas application apparatus