bluuebunny/crossref_metadata_2025_split huggingface dataset:
Beam generations of three kinds of charged particles
Authors: Niu K. , Mulser P. , Drska L. 
Published: March 2009

Analyses are given for beam generations of three kinds of charged particles: electrons, light ions, and heavy ions. The electron beam oscillates in a dense plasma irradiated by a strong laser light. When the frequency of laser light is high and its intensity is large, the acceleration of oscillating electrons becomes large and the electrons radiate electromagnetic waves. As the reaction, the electrons feel a damping force, whose effect on oscillating electron motion is investigated first. Second, the electron beam induces the strong electromagnetic field by its self-induced electric current density when the electron number density is high. The induced electric field reduces the oscillation motion and deforms the beam.In the case of a light ion beam, the electrostatic field, induced by the beam charge, as well as the electromagnetic field, induced by the beam current, affects the beam motion. The total energy of the magnetic field surrounding the beam is rather small in comparison with its kinetic energy.In the case of heavy ion beams the beam charge at the leading edge is much smaller in comparison with the case of light ion beams when the heavy ion beam propagates in the background plasma. Thus, the induced electrostatic and electromagnetic fields do not much affect the beam propagation.
Thermodynamic properties and thermal conductivity of high density deuterium
Authors: Inoue Kazuko , Ariyasu Tomio 
Published: March 2009

The phase diagram of high density (1023 ˜ 1027/cm3) deuterium is obtained by calculation. The values of specific heat, electrical resistivity and thermal conductivity in the metallic state are estimated over a wide range of temperature (10−2 ˜ 104 eV). The temperature dependences of these properties are shown in figures with the density. When T ≤ Tf (Tf: the Fermi temperature of electrons), the behavior is very similar to those of normal metals. At high temperatures where T ≥ Tf, the behavior is similar to that of completely ionized classical plasma.This fundamental data for deuterium will help us understand the properties of fuel in inertial-confinement fusion and to solve the fluid equations for efficient compression of fuel pellets.
Current neutralization of ion beam rotating and propagating in plasma
Authors: Aoki Takayuki , Niu Keishiro 
Published: March 2009

The current-neutralization fraction of a rotating and propagating light ion beam (LIB) injected into a low density plasma is investigated numerically. The beam space charge is essentially neutralized by a redistribution of the background plasma electrons in a time duration equal to the inverse of electron plasma frequency. When the density of the background plasma is comparable with that of the beam, incomplete current neutralization occurs because the strong magnetic field induced by the intense ion beam restricts the return plasma current.In the simulation, the ion beam and the background plasma are treated as the fluids coupled with Maxwell's equations and Ohm's law, including the effect of the magnetic field on electrical conductivity. The calculations assume that the ion beam is injected in an unsteady fashion into the uniform plasma. It is found that the return current strongly depends on the density of the background plasma. The beam deceleration and the acceleration of the beam head and tail are also considered.
Low-fluence laser–target coupling
Authors: Combis P. , Cazalis B. , David J. , Froger A. , Louis-Jacquet M. , Meyer B. , Nierat G. , Saleres A. , Sibille G. , Thiell G. , Wagon F. 
Published: March 2009

Low-fluence laser interaction with metallic target is investigated in a wide range of irradiance, from 5 × 106 to 1011 W/cm2, with 4- and 30-ns laser-pulse durations and 1.06-μm wavelength. Edge effects are avoided by means of large surfaces of irradiation (5 cm2). Specific diagnostics such as a ballistic pendulum and a piezoelectric quartz gauge are developed to measure the total momentum imparted to the target, as well as the temporal evolution of the stress at the rear side of the target. Specular reflection and sidescattering of the laser light from the target are also measured. The behavior of 2024 aluminum alloy is particularly studied. The results are interpreted in terms of liquid-vapor transition and change in laser absorption.In light of experimental data, the theoretical analysis of surface absorption is reviewed, showing the dependence on metal temperature and laser wavelength. The thermal and mechanical coupling is also calculated.Numerical simulations are performed with a 1–D Lagrangian hydrodynamic code including modifications for low-pressure regimes. The multiphase equation of state is extended to take into account negative pressures. An elastoplastic module is introduced into the code. A quite good agreement is obtained with the measurements of the stress and of the mechanical coupling coefficient.
Experiments on high-power ion beam generationin self-insulated diodes
Authors: Bystritskii V. M. , Glyshko Yu. A. , Sinebrjukhov A. A. , Kharlov A. V. 
Published: March 2009

Experimental results are given on high-power ion beams (HPIB) generation in a vacuumspherical focusing diode with self-magnetic insulation, obtained from the nanosecond accelerator PARUS with 0.2-TW power and 60-ns pulse duration for a matched load. When the passive plasma source of the ions was used, the efficiency of the HPIB generationwas measured to be as high as 20% for 700-kV diode voltage and 10-kA/cm2 beam density in the focal plane.The application of a coaxial plasma opening switch (POS) prior to the diode resultedin a factor-of-1.8 increase in the diode power in comparison with a match operation inthe absence of a POS.
Nova Upgrade Program: Ignition and beyond
Authors: Storm E. , Campbell E.M. , Hogan W.J. , Lindl J.D. 
Published: March 2009

The Lawrence Livermore National Laboratory (LLNL) Inertial Confinement Fusion (ICF) Program is addressing the critical physics and technology issues directed toward demonstrating and exploiting ignition and propagating burn to high gain with ICF targets for both defense and civilian applications. Nova is the primary U.S. facility employed in the study of the X-ray-driven (indirect drive) approach to ICF. Nova's principal objective is to demonstrate that laser-driven hohlraums can achieve the conditions of driver-target coupling efficiency, driver irradiation symmetry, driver pulseshaping, target preheat, and hydrodynamic stability required by hot-spot ignition and fuel compression to realize a fusion gain.The LLNL ICF Program believes that the next major step in the national ICF Program is the demonstration of ignition and moderate gain (G ≤ 10). Recent theoretical and experimental results show that the ignition drive energy threshold can be reduced significantly by operating indirectly driven targets at radiation temperatures ∼ 1.3–1.6 times higher (thereby achieving higher implosion velocity) than originally proposed for the Laboratory Microfusion Facility (LMF). (Temperatures of ∼ 1.3 times higher have already been demonstrated on Nova.) Specifically, it should be possible to demonstrate ignition and propagating with burn about 1–2 MJ of laser energy as against the 5–10 MJ necessary for the high-yield LMF. LLNL proposes to upgrade the existing Nova facility to 1–2 MJ (2- to 4-ns pulses) and demonstrate ignition and propagating burn to moderate gain with appropriately scaled hydrodynamic equivalents of high-yield targets.Once moderate gain has been demonstrated at 1–2.0 MJ on the Nova Upgrade, investigations into improving, by about 50%, the coupling efficiency between the driver and the capsule could provide gains >20 at about 1 MJ or less. A database for gain below 1-MJ driver energies could lead to a low-capital-cost Engineering Test Facility (ETF) for a first inertial fusion energy engineering reactor. Because the capital cost for both the target chamber and the driver scale with size, there is the opportunity to realize large savings by lowering the required driver energy necessary to demonstrate the technology for a first demonstration power plant. A target gain, G ∼ 25, at a driver energy, ED ∼ 0.75 MJ, would be self-sustaining for a driver efficiency of ∼10% and a thermal-to-electric conversion efficiency of ∼33% and at 12 Hz would generate ∼10 MW of gross electric power. Although the cost of electricity would be high, the combination of low capital cost and early demonstration of reactor technology would be an attractive step in the development of inertial fusion energy.
Cosmology in the Plasma Universe
Authors: Alfvén Hannes 
Published: March 2009

Space observations have opened the spectral regions of X-rays and γ-rays, which are produced by plasma processes. ThePlasma Universederived from observations in these regions is drastically different from the now generally accepted ‘Visual Light Universe’ based on visual light observations alone. Historically this transition can be compared only to the transition from the the geocentric to the heliocentric cosmology.The purpose of this paper is to discuss what criteria a cosmological theory must satisfy in order to be acceptable in the Plasma Universe.
Acceleration in the plasma focus and in astrophysics
Authors: Browne P. F. 
Published: March 2009

Both, in the laboratory (specifically the plasma focus) and in astrophysics, charges are accelerated in magnetically pinched current channels. The current channels are annular cylinders, defined by an electric double layer of thickness δrE and radius R due to radial polarization of the plasma. The electric field Er in the double layer and the azimuthal magnetic field Bϕ ensure drifts of charges in the axial direction, but ions do not take up the full drift velocity because their Larmor radius exceeds δrE. Magnetic pinching of the channel reduces the cross sectional area S, and an instability of drift velocity may denude a region of current channel. The inductively maintained current J then cannot be carried by free charges, even with relativistic drift velocity. A displacement current (S/4π) δEz/δt arises, Ez growing until all energy in Bϕ is transferred into Ez. During this transfer Bϕ decreases, so the pinch weakens, permitting discharge of accumulated space charge via a conduction current without reversal of J. Thereafter the cycle repeats quasi-periodically.In astrophysics acceleration occurs in a pinched magnetic vortex tube (MVT). The difference is that now Bϕ(r, +z) = −Bϕ(r, −z) due to winding of loops of field lines. Hence J reverses across mid-pinch, which implies accumulation of space charge of one sign at mid-pinch and of opposite sign at the ends of the pinch. Now there is reversal of J when the space charge relaxes.
Industrial applications of pulse power and particle beams
Authors: Yatsui Kiyoshi 
Published: March 2009

An overview is given of recent progress in the industrial applications of intense pulse power and associated particle beams, except for activities in inertial confinement fusion. In particular, several topics are discussed which relate to the applications in the R&D of materials, the excitation of short wavelength lasers, the generation of charged particle beams, and the development of plasma X-ray sources.I. Applications in material processing. If intense pulsed charged particle beams are directed onto materials, only their surfaces where the beam energy is deposited are quickly heated up to very high temperatures. Using the pulsed beam in this way, we might expect to apply them in R&D of materials. Several novel attempts have been made, e.g., on the preparation of thin films by use of a high-density high-temperature plasma, surface modification by surface heating, and ion-beam mixing of multi-layers by use of the focused electron or ion beams, and so on. Furthermore, experimental studies have been done on the surface modification by ion implantation and the evaluation of the damage due to the irradiation by ion beams.II. Applications in the excitation of short wavelength lasers. Activities in the excitation of high-power, short wavelength lasers by using electron beams or ion beams have increased considerably.III. Applications in the generation of charged particle beams, and the development of plasma X-ray source. With regard to new accelerator technologies, several attempts are underway on the application of the modified betatron or the development of a convergent electron beam accelerator with a plasma cathode.
Principles of non-Liouvillean pulse compression by photoionization for heavy-ion fusion drivers
Authors: Hofmann Ingo 
Published: March 2009

Photoionization of single-charged heavy ions has been proposed recently by Rubbia (1989) as a non-Liouvillean injection scheme from the linac into the storage rings of a driver accelerator for inertial confinement fusion. The main idea of this scheme is the accumulation of high currents of heavy ions without the usually inevitable increase of phase space. Here we suggest the use of the photoionization idea in an alternative scheme: if it is applied at the final stage of pulse compression (replacing the conventional bunch compression by an rf voltage, which always increases the momentum spread), there is a significant advantage in the performance of the accelerator. We show, in particular, that this new compression scheme can potentially relax the tough stability limitations, which were identified in the heavy-ion fusion reactor study HIBALL (Badger et al. 1984). Moreover, it is promising for achieving higher beam power, which is suitable for indirectly driven fusion targets (1016 W/g, in contrast with 1014 W/g for the directly driven targets in HIBALL).The idea of non-Liouvillean bunch compression is to stack a large number of bunches (typically 50–100) in the same phase-space volume during a change of charge state of the ion. A particular feature of this scheme with regard to beam dynamics is its transient nature, since the time required is one revolution per bunch. After the stacking the intense bunch is ejected and directly guided to the target. The present study is a first step in exploring the possibly limiting effect of space charge under the parameter conditions of a full-size driver accelerator. Preliminary results indicate that there is a limit to the effective stacking number (non-Liouvillean “compression factor”), which is, however, not prohibitive. Requirements on the power of the photon beam from a free-electron laser are also discussed. It is seen that resonant cross sections of the order of 10−15 cm2 lead to photon beam powers of a few megawatts.
Heating matter by intense heavy ion beams at SIS energies
Authors: Schneider V. , Maruhn J. 
Published: March 2009

The hydrodynamic flow in cylindrical aluminum targets irradiated by intense Xenon beams is discussed for three different beam-target combinations. Solid targets, targets with enclosed cavities, and hollow beams are considered to study the effects of energy deposition and compression waves in matter. Emphasis is put on the occurrence of converging shock waves. The assumed beam intensity of 40TW/cm2 is in the scope of the GSI-SIS/ESR facility that will start operating in 1990/91.A two-dimensional hydrodynamic code, including the energy deposition of heavy ions, a realistic equation of state, and realistic transport coefficients, is used in numerical simulations to obtain information on the temperature and density distributions and the relevant time scales that have to be expected in these experiments.
An investigation into the use of a non-metallic deodorant during radiotherapy treatment: a randomised controlled trial
Authors: Bennett Claire 
Published: March 2009

AbstractIntroduction: Many patients in the United Kingdom having radiotherapy for breast cancer are recommended not to use a deodorant during treatment. The advice is not evidence based, it is solely thought as deodorants contained metals, which would react with radiation and cause an increased skin reaction. Hence this research was undertaken to establish whether patients having a course of radiotherapy for breast cancer could use a deodorant as part of their daily routine.Method: The research took place between May 2004 and February 2005. A total of 192 breast cancer patients were recruited. This included breast or chest-wall patients with or without axilla involvement. The study was designed with two groups. Group 1 used no deodorant and Group 2 a specific deodorant. The researcher reviewed patients weekly, assessing skin reactions and recording the researcher and patient's observations.Results: Most patients experienced no reaction or mild erythema and dry desquamation in the axilla. This was observed in both groups. Therefore, findings of this study indicate that future breast cancer patients should be given the choice of using this deodorant.Further recommendations: Test the reliability of the skin assessment form, extend the research to include other patient groups who have their axilla treated, test different deodorants.
Addressing the information needs of patients with prostate cancer: A literature review
Authors: Mc Parland Neil A. 
Published: March 2009

AbstractPsychosocial support is a cornerstone in the holistic care of cancer patients. The provision of information is a key tool in the psychosocial management of the cancer patient, and it is important that the therapy radiographer is cognizant of the patient's need for information.This article reviews the importance of information to the psychosocial well-being of cancer patients in general, with specific emphasis on patients with prostate cancer. The information services at a large Canadian cancer facility are also reviewed to gain some insight into how the needs of patients with prostate cancer are addressed at the author's workplace.Most patients with prostate cancer have an expressed need for considerable amounts of information at various stages of their cancer journey. The provision of information has a range of benefits to the prostate patient such as helping the patient deal with their diagnosis, assisting with the decision-making process and reducing anxiety.Interpersonal sources of information such as face-to-face communication with the oncologist or radiation therapist are preferred by many patients, including patients with prostate cancer. Other sources that include the internet and written hospital material are also used with varying degrees of effectiveness to deliver information.The provision of quality information in a timely and effective manner cannot be taken for granted. Access to appropriate information resources can be impeded because of poorly designed information material, inadequate communication, ineffective signposting, resource constraints and lack of knowledge/comprehension on the part of frontline health-care workers dealing with the patient. Radiation therapists are encouraged to be advocates for their patients’ information needs and to be involved in initiatives that will improve the quality, dissemination and efficacy of information.
Determination of target volumes in radiotherapy and the implications of technological advances: a literature review
Authors: Mzenda Bongile , Hosseini-Ashrafi M.E. , Palmer A. , Hodgson D.F. , Liu H. , Brown D.J. 
Published: March 2009

AbstractThis study assesses the influence of new techniques and technologies in radiotherapy on the derivation and applicability of the margins currently used for treatment planning. The validity of the continued use of the recommendations of International Commission on Radiation Units and Measurements (ICRU) and other recommendations as a result of the additional information derived from these emerging techniques is also reviewed. The ICRU formulations still remain fundamental in the derivation of target volumes in radiotherapy; however, revisions to these have been recommended through various experimental and modelling techniques leading to the publication of various margin recipes. These recipes are used for margin definitions in new radiotherapy techniques including intensity-modulated radiotherapy (IMRT). The use of image-guided radiotherapy (IGRT) techniques leads to the reduction in organ motion uncertainties and setup errors, allowing for the adjustment of margins and treatment plans as well as dose escalation. Clinical trials are still needed to validate most of the new techniques in radiotherapy, particularly in IGRT techniques leading to adaptive radiotherapy. It is recommended that well devised clinical trials should be conducted to investigate fully the efficacy of these new techniques, particularly in radiotherapy image guidance and adaptive radiotherapy. Such trials would validate any recommendations regarding the current clinical margins and impact on their continued clinical use.
Neonatal respiratory morbidity and mode of delivery in a population‐based study of low‐risk pregnancies
Authors: FARCHI SARA , DI LALLO DOMENICO , FRANCO FRANCESCO , POLO ARIANNA , LUCCHINI RENATO , CALZOLARI FLAMINIA , DE CURTIS MARIO 
Published: March 2009

AbstractThe aim of this study is to evaluate the association between the mode of delivery and the risk of neonatal respiratory complications in a cohort of term newborns in the Lazio region, Italy. Data on 139,379 term singleton infants born in 2003–2005 were retrieved from birth and hospital discharge database. Odds Ratios (ORs) adjusted by age, parity, birth weight, gestational age, and gender were calculated using logistic regression models. The rate of prelabor cesarean section (CS) was 26.2%. The rates of neonatal respiratory morbidity were 29.6/1,000 in infants delivered by prelabor CS and 17.4/1,000 in infants delivered vaginally or by CS in labor. The adjusted risk of neonatal respiratory morbidity associated with prelabor cesarean birth at 37 weeks is four times higher than in intended vaginal birth after 37 weeks. Prelabor cesarean delivery should be performed after at least 38 weeks’ of gestation in order to minimize neonatal respiratory morbidity.
An Interactive, Source-Centric, Open Testbed for Developing and Profiling Wireless Sensor Systems
Authors: Dalton Andrew R. , Hallstrom Jason O. 
Published: March 2009

The difficulty of developing wireless sensor systems is widely recognized. Problems associated with testing, debugging, and profiling are key contributing factors. While network simulators have proven useful, they are unable to capture the subtleties of underlying hardware, nor the dynamics of wireless signal propagation and interference; and physical experimentation remains a necessity. To this end, developers increasingly rely on shared deployments exposed for physical experimentation. Sensor network testbeds are under development across the world. We present a complementary testbed architecture that derives its novelty from three characteristics. First, the system is interactive; users can profile source and network level components across a network in real time, as well as inject transient state faults and external network traffic. Second, the system is source-centric; it enables automated source code analysis, instrumentation, and compilation. Finally, the design is open; developers can extend the set of exposed inter faces as appropriate to particular projects without modifying the underlying middleware. We present the testbed design and implementation, a graphical user interface, a shell-based macro programming interface, example scenarios that illustrate their use, and discuss the testbed's application in the research and teaching activities at client institutions.