bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stability of plasmas penetrated by neutral gas
Authors: Lehnert B. 
Published: January 2011

For a plasma body of density n and characteristic macroscopic dimension Lcthere exists a critical ion density nc= 1/σcmLcwhere σcm≃ 3 × 10−19m2for hydrogen. When n ⪅ ncthe plasma is permeable to neutral gas, whereas it becomes impermeable to the same gas when n ≫ nc. Permeable and impermeable plasmas have different equilibrium and stability properties. So far, tokamak experiments have been performed in the range of permeable plasmas, whereas full-scale steadystate fusion reactors are likely to operate in the impermeable range.The effects of plasma-neutral-gas interaction, finite resistivity, and viscosity on the gravitational instability modes of a magnetized plasma have been investigated:There are both direct and indirect neutral-gas effects on the ballooning and flute modes. The direct effects are due to frictional forces from collisions, and the indirect ones to the influence of the plasma-neutral-gas balance on the unperturbed pressure and density distributions.In an impermeable plasma, the driving mechanism of the ballooning and flute instabilities can be localized to a narrow, dense and cool, partially ionized boundary region, in which plasma-neutral-gas collisions and viscosity strongly reduce the instability growth rates. Further reductions of these rates are expected to arise in more advanced and non-linear approaches.In tokamaks, resistive ballooning modes should be practically unaffected by neutral-gas collisions. However, when n approaches ncfrom below, a collisionless ballooning mode is expected to arise from an increase of the gradients in the boundary region. This behaviour is consistent with observations, including adiabatic-compression experiments.
Flute perturbations of plasma in a helical magnetic field
Authors: Mikhailovskaya L.V. , Kikhailovsky A.B. 
Published: January 2011

This paper investigates flute perturbations of a plasma that is in a helical, cylindrically symmetric magnetic field. In a geometricaloptics approximation an- equation has been obtained that relates the frequency and the wave vector of the flute perturbations of the plasma for an arbitrary relation of the gas pressure and the magnetic pressure and for an arbitrary ratio ϱ/λ of the Larmor radius of the ions to the wavelength. This equation, is used to obtain stability criteria and increments (decrements) of flute-type oscillations under conditions when the shear in the lines of force is insignificant. The stability condition obtained thus in an approximation of zero ion Larmor radius coincides with the corresponding results that follow from the hydrodynamics of Chew, Goldberger, Low. For small values of β and a finite ratio ϱ/λ a criterion was obtained for the stabilization of perturbations with finite ion Larmor radius.
Consideration of interaction between resonance particles and the wave in a number of cases leads to the buildup of flute perturbations. It is shown that such a type of buildup—residual instability—in the case of a helical magnetic field differs essentially from the residual instability for a model with a force of gravity discussed in the paper by Rosenbluth. Krall and Rostoker which is due to differences in the direction of the drift of the resonance particles in the two cases.
We have elucidated the connection between the waves that are responsible for flute instability of a hydrodynamic type and waves that have been revealed in the work of Yu. A. Tserkovnikov. We have considered transition to the case of a magnetic field with an infinitely large radius of curvature of lines of force. We have elucidated the question of the spatial structure (in a radial direction) of waves of the type discussed in Ref 5, and it has been shown that their radial wavelength is essentially connected with the ion Larmor radius, and the wavelength of hydrodynamic flute perturbations does not depend on the value of the latter.
The effect of curvature of lines of force on flute perturbations of the type of transverse drift waves has been discussed. We have shown that for not too large a radius of curvature of the line of force R <a/β (a is the characteristic dimension for the change of plasma pressure), the instability predicted in the work of Krall and Rosenbluth [6] for such a type of oscillations in a field with R→ ∞ is stabilized.
Scattering of electromagnetic waves by a cylindrical plasma in a steady magnetic field: I. Anisotropy effects
Authors: Vandenplas P. E. , Messiaen A. M. 
Published: January 2011

The experimental resonance pattern of a cylindrical plasma in a steady magnetic field is compared to theory. The scattering of a plane homogeneous wave by a cold plasma column with a glass wall is studied theoretically. The Poynting vector of this wave is perpendicular to the axis of the cylinder. The static magnetic field B0 is parallel either to the axis or to the Poynting vector S, or perpendicular to both the axis and S.
The equilibrium density of the cold plasma is assumed constant in this paper and the anisotropy effects due to the homogeneous steady magnetic fields are studied through the equivalent tensorial permittivity. This permittivity is written in a general form so that the treatment also includes the anisotropie dielectric rod. When B0 lies in the cross-section of the cylinder, the partial differential equations cannot be solved in cylindrical co-ordinates. The solution is however obtained to second order in β (dimensionless parameter proportional to B0) in a Cartesian co-ordinate system and it is then transformed to a cylindrical system in which the boundary conditions are stated. It is found in most cases that the effect of B0 is much greater for the experimental phenomena than that predicted by the theoretical approach. This discrepancy arises from Laplace forces due to B0 in the cross-section and to the drift velocity of the electrons along the axis of the cylinder, and results in an inhomogeneity of magnetic origin studied in part II. This magnetically induced inhomogeneity accounts for the data not explained by the anisotropie approach.
When B0 is parallel to the cylinder axis, the problem is solved exactly. The aforesaid Laplace forces do not intervene as B0 is then parallel to the drift velocity. The quantitative agreement is very satisfactory for relatively small values of B0 and poorer results for higher B0 are probably linked to non-proportionality between equilibrium electron density and the discharge current in the plasma column.
Drift cyclotron instability of a plasma with hot ions
Authors: Mikhailovsky A.B. 
Published: January 2011

The author analyzes the role of drift-cyclotron instability, alluded to in ref. 2, in a spatially inhomogeneous plasma. This instability can occur in a not-too-dilute plasma with a finite Larmor radius of the ions, (ϱ/a)2 > (CA/C)2; (CA is the Alfvén velocity, ϱ is the Larmor radius of the ions, and a is the characteristic dimension of the inhomogeneity).
The paper contains a detailed investigation of the effects on the instability criterion of various factors: the curvature of the lines of force and the inhomogeneity of the magnetic field, the form of the equilibrium particle velocity distribution function, the relationship between the transverse and longitudinal dimensions of the system, and the ratio of electron to ion temperature.
The author concludes that, if the flute (hydrodynamic) instability is stabilized, the drift-cyclotron instability is the most dangerous for a system with a finite Larmor radius of the ions. This instability may be overcome by creating a system with finite intersection of the magnetic lines of force (shear). In short systems this instability need not occur if there is cold plasma of finite density between the hot plasma and the conducting ends of the apparatus.
Electrical conductance of a turbulent plasma
Authors: Petviashvili V.I. , Ramazashvili R.R. , Tsintsadze N.L. 
Published: January 2011

We investigate the electrical conductance of a homogeneous, weakly turbulent magnetoactive plasma under the assumption that oscillation is possible. Under certain onditions the electrical conductance of such a plasma can be anomalously small. This phenomenon can be explained by an effective increase in the frequency of ion electron collisions that is caused by collective particle interaction. Only low-frequency oscillations (in which both electrons and ions participate) give a significant contribution to turbulent-plasma resistance.
A formula was found, through the turbulent oscillation spectrum, for the electrical conductance of the weakly turbulent plasma. Comparison of the conductance with the anomalous diffusions across the magnetic field shows that they both contain the same quantity (determined by the oscillation spectrum), which can be interpreted as an effective collision frequency; hence we draw the conclusion that this effective collision frequency will play the role of ordinary collisions in other macroscopic processes also.
The effective collision frequency was evaluated for the Drummond-Rosenbluth instability, and with it we found the width of the weak shock wave in collisionless plasma. Also found was the formula for the effective collision frequency of an isotropic plasma.
Diffusion perpendicular to the magnetic field in the universal instability
Authors: Buchelnikova N. S. 
Published: January 2011

Diffusion perpendicular to the magnetic field is investigated in a potassium plasma of non-uniform density in which the “universal” instability is excited. A qualitative picture of such diffusion is obtained by studying the relationship between the radial distribution of plasma density and the magnetic field, and by comparing the experimental densities with calculated ones on the assumption of classical diffusion. For densities of 109—1010 cm−3, the radial distribution and the peak density do not depend on the magnetic field. At higher densities, however, the half-width of the distribution becomes smaller and the peak diminishes as the field increases. At densities of 7 × 1010—5 × 1011 cm−3 the curves for the radial distribution agree well with the calculations.
Direct measurements of the diffusion coefficient come from measurements of the plasma flux perpendicular to the magnetic field. In the density range 109—1010 cm−3, the diffusion coefficient does not depend on magnetic field or on density. At higher densities it does depend on the magnetic field H, and at densities greater than 2 × 1011 cm−3 a 1/H
2 relationship is observed; the diffusion coefficient agrees with the classical coefficient in absolute value. The spread in the diffusion coefficients obtained from a single series of experiments, representing the statistical accuracy of the measurements and the stability of the diffusion coefficient, is ∼40%. The average value of the diffusion coefficient for low densities is (2.3 ± 0.9) × 102 cm2/s, greater than the classical coefficient by 1 to 2 orders of magnitude. The diffusion coefficient and the oscillation amplitude are correlated. As density is varied they remain constant until a certain critical density is reached, after which they begin to decline simultaneously. Classical diffusion is observed in the region where instability is control. Ion-ion diffusion and wall diffusion play no part in the experiments. The conclusion is drawn that the diffusion coefficient measured in the density range 109—1010 cm−3 is the result of the universal instability in a collisionless plasma.
Equilibrium of a toroidal plasma column in steady-state and high-frequency magnetic fields
Authors: Gutkin T.I. , Lozovsky S.N. , Boleslavskaya G.I. 
Published: January 2011

The authors consider the equilibrium of a toroidal plasma column in a steady-state magnetic field on which is superimposed a multipole high-frequency field produced by currents flowing around the major circumference of the torus which are proportional to exp[i (ωt-nψ)], where ψ is the polar angle in the meridional cross-section of the torus and ω is the frequency determined by the generator.
They demonstrate the possibility of achieving equilibrium when the pressure of the high-frequency field is less than the kinetic pressure of the plasma, ignoring the reaction of the circuit to the displacement of the plasma column; i.e. it is assumed that this displacement does not give rise to image currents in the circuit.
An expression is derived for displacement of the column as a function of the amplitude of the high-frequency field, the kinetic pressure of the plasma, the depth of the skin layer, the multipole order (n), and of geometric parameters such as the radius of the plasma column rp, the radius of the circuit rk and the radius of the torus R. The displacement of the column is proportional to the kinetic pressure of the plasma, inversely proportional to the square of the amplitude of the current in the circuit, and independent of the steady-state magnetic field. Expressed as a function of the multipole order (n), displacement is at a minimum when n is equal to the whole number closest to 1 + [1/2 ln(rk/rp)]. When rk/rp∼2, the optimum value of n is 2 (quadrupole). When n = 1 (dipole), displacement increases in proportion to ln(c/ωrp). On the assumption of a quasi-steady state (c/ωrp ≫ 1) equilibrium containment of the plasma in the dipole case is found to be difficult to achieve in practice. When n = 0 equilibrium is quite impossible to achieve. The validity of this conclusion is dependent on the assumption of a quasi-steady state and on the further assumption that the circuit will not react to displacement of the column.
Application of lasers to the production of high-temperature and high-pressure plasma
Authors: Kidder R.E. 
Published: January 2011

A brief account is given of the historical evolution of giant pulse lasers and of the level of performance of such lasers that has so far been achieved. Those aspects of the interaction of light with a plasma that are of importance in plasma heating are briefly reviewed, and a detailed treatment including the results of computer calculations is given of the heating of a spark within a homogeneous gas, the subsonic heating of an isolated gas sphere, and the pressure resulting from light-induced blow-off.
It is concluded that existing giant pulse lasers have sufficient brightness to be potentially capable of producing plasmas with kilovolt temperatures and tens of megabar pressures, but that a major increase in output power will be required before this potential can be realized. The design of future giant pulse lasers that are particularly well suited to the achievement of extremely high output power at high brightness is discussed.
Kinetics of slightly relativistic plasma, II
Authors: Trubnikov B.A. 
Published: January 2011

A solution has been found to the equation obtained earlier for the binary correlation function of an electron plasma; this equation takes into account, in the first non-vanishing approximation, effects of interaction retardation. Transverse interactions of particles at great distances are shown to diminish proportionally to r−3, as a result of which an isolated particle in the plasma is surrounded by a very extensive correlation cloud of currents.
The collision integral obtained on the basis of Darwin's Lagrangian is shown to differ from one making precise allowance for retardation only in terms of the order (v/c)6.
Langmuir probes compared with other diagnostic techniques in a Q-device
Authors: Van Der Houven Van Oordt A.J. , Wegrowe J.-G. 
Published: January 2011

A comparison of density measurements between cylindrical Langmuir probes, resonance fluorescence scattering and microwave methods is performed in a singly ionized barium plasma of a Q-device by varying the following parameters: 1) Density n: 3 × 108 cm−3 ≤ n ≤ 3 × 1011 cm−3; 2) Plate temperature Tp: 2100°K ≤ Tp ≤ 2500°K; 3) Plate material: Re and W; 4) Magnetic field B: 2 kG ≤ B ≤ kG; 5) Mode of operation: Double and single ended operations; 6) Ion temperature Ti down to about room temperature, keeping the electron temperature Te = Tp; 7) Degree of ionization γ: 0.1% ≤ γ ≤ 100%; 8) Probe dimensions.
If the density n is evaluated by equating the extrapolated ion saturation current Is at the plasma potential Vs to the random ion current, it is shown that this yields a reliable relative value of the plasma density, which is by a factor of about 2.5 higher than the most probable value.
Equations of the electromagnetic field containing plasma
Authors: Karlovitz Béla 
Published: January 2011

Plasma differs from all other media in the nature of its diamagnetic moment. The motion of the free ions and electrons, responsible for the magnetic moment of the plasma, is not restricted by quantum rules. Consequently, the energy transfer mode cE⃗⋅curlM⃗, which is forbidden by Maxwell's equations for all other media, does exist between plasma and field. Full description of an electromagnetic field containing plasma therefore requires additional terms in the field equations. These terms allow the existence of a new phenomenon: the generation of steady-state electrical vortex fields measured in a coordinate system at rest relative to the time-constant magnetic field.
The characteristic properties of this plasma-generated induction phenomenon are described briefly. The need for an experimental test of the predicted phenomenon is stressed, particularly in view of the great simplifications it may offer for the realization of thermonuclear power.
Temperature in laser-created deuterium plasmas
Authors: Bobin J.L. , Delobeau F. , De Giovanni G. , Fauquignon C. , Floux F. 
Published: January 2011

The beam of a powerful neodymium glass laser is focused into a solid deuterium stick. The temperature of the created plasma is measured by Jahoda's X-ray absorption method. The electron temperature has been found to range up to 450 eV and exhibits a 2/3-power dependence on the power flux density.
These results are in agreement with a theoretical model involving a strong shock and a deflagration front propagating inwards the D2 ice whereas the plasma expands in the vacuum towards the incoming beam.
Uniqueness of finite total curvatures and the structure of radial solutions for nonlinear elliptic equations
Authors: Chern Jann-Long , Chen Zhi-You , Tang Yong-Li 
Published: January 2011

In this article, we are concerned with the semilinear elliptic equation
\[

Δ
u
+
K
(

|

x

|

)

|

u

|

p
−
1

u
=
0

in

R

n

∖
{

0

}
,

\Delta u+K(|x|)|u|^{p-1}u=0\quad \textrm {in}\ \mathbf {R}^n\setminus \{\mathbf {0}\},

\]
where

n
>
2

n>2

,

p
>
1

p>1

, and

K
(

|

x

|

)
>
0

K(|x|)>0

in

R

n

\mathbf {R}^n

. The correspondence between the initial values of regularly positive radial solutions of the above equation and the associated finite total curvatures will be derived. In addition, we also conduct the zeros of radial solutions in terms of the initial data under specific conditions on

K
K

and

p
p

. Furthermore, based on the Pohozaev identity and openness for the regions of initial data corresponding to certain types of solutions, we obtain the whole structure of radial solutions depending on various situations.
Nitrous Oxide Diffusion and the Second Gas Effect on Emergence from Anesthesia
Authors: Peyton Philip J. , Chao Ian , Weinberg Laurence , Robinson Gavin J. B. , Thompson Bruce R. 
Published: January 2011

Background
Rapid elimination of nitrous oxide from the lungs at the end of inhalational anesthesia dilutes alveolar oxygen, producing "diffusion hypoxia." A similar dilutional effect on accompanying volatile anesthetic agent has not been evaluated and may impact the speed of emergence.

Methods
Twenty patients undergoing surgery were randomly assigned to receive an anesthetic maintenance gas mixture of sevoflurane adjusted to bispectral index, in air-oxygen (control group) versus a 2:1 mixture of nitrous oxide-oxygen (nitrous oxide group). After surgery, baseline arterial and tidal gas samples were taken. Patients were ventilated with oxygen, and arterial and tidal gas sampling was repeated at 2 and 5 min. Arterial sampling was repeated 30 min after surgery. Sevoflurane partial pressure was measured in blood by the double headspace equilibration technique and in tidal gas using a calibrated infrared gas analyzer. Time to eye opening and time extubation were recorded. The primary endpoint was the reduction in sevoflurane partial pressures in blood at 2 and 5 min.

Results
Relative to baseline, arterial sevoflurane partial pressure was 39% higher at 5 min in the control group (P < 0.04) versus the nitrous oxide group. At 30 min the difference was not statistically significant. Time to eye opening (8.7 vs. 10.1 min) and time to extubation (11.0 vs.13.2 min) were shorter in the nitrous oxide group versus the control group (P < 0.04).

Conclusions
Elimination of nitrous oxide at the end of anesthesia produces a clinically significant acceleration in the reduction of concentrations of the accompanying volatile agents, contributing to the speed of emergence observed after inhalational nitrous oxide anesthetic.
Toll-like Receptor 4 Signaling Confers Cardiac Protection against Ischemic Injury via Inducible Nitric Oxide Synthase- and Soluble Guanylate Cyclase-dependent Mechanisms
Authors: Wang E , Feng Yan , Zhang Ming , Zou Lin , Li Yan , Buys Emmanuel S. , Huang Peigen , Brouckaert Peter , Chao Wei 
Published: January 2011

Background
Prior administration of a small dose of lipopolysaccharide confers a cardiac protection against ischemia-reperfusion injury. However, the signaling mechanisms that control the protection are incompletely understood. We tested the hypothesis that Toll-like receptor 4 (TLR4) mediates the ability of lipopolysaccharide to protect against cardiac ischemia-reperfusion injury through distinct intracellular pathways involving myeloid differentiation factor 88 (MyD88), TIR-domain-containing adaptor protein-inducing interferon-β-mediated transcription factor (Trif), inducible nitric oxide synthase (iNOS), and soluble guanylate cyclase (sGC).

Methods
Wild-type mice and genetically modified mice, that is TLR4-deficient (TLR4(-def)), TLR2 knockout (TLR2(-/-)), MyD88(-/-), Trif(-/-), iNOS(-/-), and sGCα1(-/-), were treated with normal saline or 0.1 mg/kg lipopolysaccharide intraperitoneally. Twenty-four hours later, isolated hearts were perfused in a Langendorff apparatus and subsequently subjected to 30 min global ischemia and reperfusion for as long as 60 min. Left ventricular function and myocardial infarction sizes were examined.

Results
Compared with saline-treated mice, lipopolysaccharide-treated mice had markedly improved left ventricular developed pressure and dP/dt(max) (P < 0.01) and reduced myocardial infarction sizes (37.2 ± 3.4% vs. 19.8 ± 4.9%, P < 0.01) after ischemia-reperfusion. The cardiac protective effect of lipopolysaccharide was abolished in the TLR4(-def) and MyD88(-/-) mice but remained intact in TLR2(-/-) or Trif(-/-) mice. iNOS(-/-) mice or wild-type mice treated with the iNOS inhibitor 1400W failed to respond to the TLR4-induced nitric oxide production and were not protected by the lipopolysaccharide preconditioning. Although sGCα(1)(-/-) mice had robust nitric oxide production in response to lipopolysaccharide, they were not protected by the TLR4-elicited cardiac protection.

Conclusions
TLR4 activation confers a potent cardiac protection against ischemia-reperfusion injury via a MyD88-dependent, but Trif-independent, mechanism. iNOS/sGC are essential for the TLR4-induced cardiac protection.