This is aa informal report Intense* primarily for lateral or limited erleraal distribution. The o... more This is aa informal report Intense* primarily for lateral or limited erleraal distribution. The opinion and condniom stated are those of tke ai-thor and nay or nay not le those of tkc Laboratory. Work performed under the auspices of tke U.S. Department of Encrg} fav the Lawrence Lii-ermore Laboraror> under Contract W-1405-Eng-4H.
The effectiveness evidence was derived from a synthesis of completed studies and authors' assumpt... more The effectiveness evidence was derived from a synthesis of completed studies and authors' assumptions. Modelling A decision tree model with a 36-week time horizon was used with sensitivity analyses and Monte Carlo simulation to evaluate the effect of uncertainty. General practitioner (GP) visits took place at weeks 2, 4, 6 and 12 after the start of the therapy. At the end of the next 12-week period, efficacy was evaluated and decisions about whether patients should be switched from escitalopram to paroxetine, or vice versa, were made. If the therapy lacked effectiveness at the end of the third 12-week, patients were referred to a specialist. Outcomes assessed in the review The outcomes estimated from the literature were: the drug-specific rate of discontinuation due to adverse events, short-term response and relapse; and
An improved version of the tandem mirror fusion reactor is presented in which a power gain factor... more An improved version of the tandem mirror fusion reactor is presented in which a power gain factor Q ~10 to 20 can be obtained at a tew 100 MWe electrical output with much simpler technology in the end plugs. The improvement is obtained by rsising the electron temperature in the encJ plugs well above that in the central cell (which would be ignited). The heating power required to Maintain the high electron temperature is greatly reduced ~ to 20 to 40 MW per plug « by creating negative depressions in the potential that serve to thermally insulate electrons in the end plugs from those in the central cell. The overall concept and several proposed methods for creating the thermal barriers are discussed in Appendix A. A reactor example 1s discussed in Appendix B. * This value can always be reduced by increasing the first wall radius if such proves to be cost effective from the wall lifetime point of view.
New materials and new design concepts are being incorporated in a new approach to an old idea - f... more New materials and new design concepts are being incorporated in a new approach to an old idea - flywheel energy storage - to create an important alternative to the electrochemical storage battery for use in electric vehicles or for stationary applications, such as computer back-up power or utility load-leveling.
Page 1. Journal of Fusion Energy, Vol. 18, No. 4, 1999 Panel Report to FESAC: Review of the 1996 ... more Page 1. Journal of Fusion Energy, Vol. 18, No. 4, 1999 Panel Report to FESAC: Review of the 1996 ITER Detailed Design Report RW Conn,1 DE Baldwin,2 RJ Briggs,3 JD Callen,4 RJ Goldston,5 RD Hazeltine,6 RE Siemon,7 and TS Taylor2 ...
The purpose @this plan is to i&rat@ a goal and a tbnely, cost-Medive strategy to &monstratejiuion... more The purpose @this plan is to i&rat@ a goal and a tbnely, cost-Medive strategy to &monstratejiuion as a viable power source ad to enable the US to benefit from its commerck+tion.
Significant progress was made during the past year in carrying out theoretical investigations pur... more Significant progress was made during the past year in carrying out theoretical investigations pursuant to the scientific mission of the Institute. These achievements may be approximately classified in terms of the following categories (often with considerable overlap): sawteeth and MHD studies, turbulence theory and plasma transport, computational plasma physics, stability theory, mathematical physics, advanced ideas, and space plasma physics-related problems. An overview of this work is contained in this report. Detailed summaries of IFS Reports written during FY-89 are given in abstract form.
A simple formula is derived, for the direct determination of the electron density profile of asym... more A simple formula is derived, for the direct determination of the electron density profile of asymmetric plasma slab, in terms of the .ac resistance of the slab as a function of frequency. The cold plasma approximation is used.
Any mechanism which couples electrostatic waves (plasma oscillations) and electromagnetic waves i... more Any mechanism which couples electrostatic waves (plasma oscillations) and electromagnetic waves in a plasma will lead to radiation from plasma oscillations. The most important consequence of nonlinearity of the equations is that two electrostatic waves are coupled to one electromagnetic wave; this process is therefore responsible for radiation at the second harmonic (2ωp). Low-frequency or static inhomogeneities of the plasma couple one electrostatic wave to one electromagnetic wave, and therefore, produce radiation at (or near) the plasma frequency. Two types of inhomogeneity are considered: ``isotropic'' inhomogeneities, which are fluctuations in the plasma density, and ``anisotropic inhomogeneities,'' which comprise an inhomogeneous distribution of currents and magnetic fields. These radiation mechanisms are analyzed by means of a set of fluid equations for the electron component, which should provide an adequate description for plasma oscillations with wavenumbers small compared with the Debye wavenumber. The radiation field is evaluated by a Green function method, ignoring re-absorption, which one expects to be a very weak process. For each radiation mechanism, a formula is obtained for the volume emissivity of a turbulent plasma representing the plasma oscillations and the inhomogeneities each by a correlation function and an energy spectrum. Useful approximate forms of these formulas are given.
P HYSI CAL RK VI K%' LKTYKRS 10 eV which is about four times the unper-turbed mean electron therm... more P HYSI CAL RK VI K%' LKTYKRS 10 eV which is about four times the unper-turbed mean electron thermal energy (determined by a Langmuir probe). Thus the assumption of the cold plasma model is not unreasonable.
The method of expansion in instantaneous eigenfunctions is used to obtain approximate solutions t... more The method of expansion in instantaneous eigenfunctions is used to obtain approximate solutions to the linearized Vlasov equation when the unperturbed function is time‐dependent. The method is useful when the time‐dependence of the unperturbed function is slow compared with the plasma frequency. The general results are used to obtain the growth of wave energies in the quasilinear limitation of weak two‐stream instabilities. Deviations from previous results for this problem are found.
This is an informal report intended primarily for internal or traited external distribution. The ... more This is an informal report intended primarily for internal or traited external distribution. The opinions and conclusions, stated are those of (lie author and may or ma? not be those of the laboratory, H'onk performed wider (I* auspices ai the IS. Departme*! of Enere* b> the Lawrence Uvconor* Laboratory und\T Contract W-7-W5-Knp*4fl-MODEL FOR ION CONFINEMENT IN A HOT-ELECTRON TANDEM MIRROR ANCHOR ABSTRACT Anisotropic, hot electrons trapped in local minitnum-B wells have been proposed as MHD-stabilizing anchors to an otherwise axisyirniet-: c tandem configuration. This work describes a im^l for plasma confiner, >nt between the anchors and the remainder of the system and calculates the piwer loss implied by maintenance of this plasma.
The high‐frequency precessional mode of a hot‐electron‐stabilized magnetic configuration has prev... more The high‐frequency precessional mode of a hot‐electron‐stabilized magnetic configuration has previously been shown to be stable in a window of core‐plasma mass. Under conditions of frequency matching, the resulting stable negative‐energy precessional wave can be destabilized by coupling to positive‐energy shear‐Alfven waves. Coupling is avoided when the hot‐electron precession frequency exceeds the core‐plasma ion gyrofrequency.
This investigation is concerned with the development of a two-body distribution function in a pla... more This investigation is concerned with the development of a two-body distribution function in a plasma for use in a kinetic equation for the one-body distribution function. The kinetic equation is obtained for a uniform plasma for those circumstances in which the time dependence of higher-order distribution functions can be assumed to occur within a functional dependence on the one-particle distribution function. The conditions of validity for this functional-dependence assumption are discussed. The resulting interaction term is new in the sense that it contains no divergent integrals requiring cutoffs, and it may be considered accurate to first order in (e 2 /kTXD). The interaction term is composed of two parts. The first is a Boltzmann collision integral with a Debye-shielded interaction. The second term is due to the deviation of the shielding cloud from a Debye shield and is the Fokker-Planck form, the coefficients of which are finite and wellbehaved. Because of its form, with a convergent collision integral and convergent Fokker-Planck coefficients, the solution may be considered as a joining of the previous solutions to this problem.
As the amplitudes of the electron-plasma waves grow they scatter the beam electrons causing the n... more As the amplitudes of the electron-plasma waves grow they scatter the beam electrons causing the nonlinear instability to saturate and finally quench.
This is aa informal report Intense* primarily for lateral or limited erleraal distribution. The o... more This is aa informal report Intense* primarily for lateral or limited erleraal distribution. The opinion and condniom stated are those of tke ai-thor and nay or nay not le those of tkc Laboratory. Work performed under the auspices of tke U.S. Department of Encrg} fav the Lawrence Lii-ermore Laboraror> under Contract W-1405-Eng-4H.
The effectiveness evidence was derived from a synthesis of completed studies and authors' assumpt... more The effectiveness evidence was derived from a synthesis of completed studies and authors' assumptions. Modelling A decision tree model with a 36-week time horizon was used with sensitivity analyses and Monte Carlo simulation to evaluate the effect of uncertainty. General practitioner (GP) visits took place at weeks 2, 4, 6 and 12 after the start of the therapy. At the end of the next 12-week period, efficacy was evaluated and decisions about whether patients should be switched from escitalopram to paroxetine, or vice versa, were made. If the therapy lacked effectiveness at the end of the third 12-week, patients were referred to a specialist. Outcomes assessed in the review The outcomes estimated from the literature were: the drug-specific rate of discontinuation due to adverse events, short-term response and relapse; and
An improved version of the tandem mirror fusion reactor is presented in which a power gain factor... more An improved version of the tandem mirror fusion reactor is presented in which a power gain factor Q ~10 to 20 can be obtained at a tew 100 MWe electrical output with much simpler technology in the end plugs. The improvement is obtained by rsising the electron temperature in the encJ plugs well above that in the central cell (which would be ignited). The heating power required to Maintain the high electron temperature is greatly reduced ~ to 20 to 40 MW per plug « by creating negative depressions in the potential that serve to thermally insulate electrons in the end plugs from those in the central cell. The overall concept and several proposed methods for creating the thermal barriers are discussed in Appendix A. A reactor example 1s discussed in Appendix B. * This value can always be reduced by increasing the first wall radius if such proves to be cost effective from the wall lifetime point of view.
New materials and new design concepts are being incorporated in a new approach to an old idea - f... more New materials and new design concepts are being incorporated in a new approach to an old idea - flywheel energy storage - to create an important alternative to the electrochemical storage battery for use in electric vehicles or for stationary applications, such as computer back-up power or utility load-leveling.
Page 1. Journal of Fusion Energy, Vol. 18, No. 4, 1999 Panel Report to FESAC: Review of the 1996 ... more Page 1. Journal of Fusion Energy, Vol. 18, No. 4, 1999 Panel Report to FESAC: Review of the 1996 ITER Detailed Design Report RW Conn,1 DE Baldwin,2 RJ Briggs,3 JD Callen,4 RJ Goldston,5 RD Hazeltine,6 RE Siemon,7 and TS Taylor2 ...
The purpose @this plan is to i&rat@ a goal and a tbnely, cost-Medive strategy to &monstratejiuion... more The purpose @this plan is to i&rat@ a goal and a tbnely, cost-Medive strategy to &monstratejiuion as a viable power source ad to enable the US to benefit from its commerck+tion.
Significant progress was made during the past year in carrying out theoretical investigations pur... more Significant progress was made during the past year in carrying out theoretical investigations pursuant to the scientific mission of the Institute. These achievements may be approximately classified in terms of the following categories (often with considerable overlap): sawteeth and MHD studies, turbulence theory and plasma transport, computational plasma physics, stability theory, mathematical physics, advanced ideas, and space plasma physics-related problems. An overview of this work is contained in this report. Detailed summaries of IFS Reports written during FY-89 are given in abstract form.
A simple formula is derived, for the direct determination of the electron density profile of asym... more A simple formula is derived, for the direct determination of the electron density profile of asymmetric plasma slab, in terms of the .ac resistance of the slab as a function of frequency. The cold plasma approximation is used.
Any mechanism which couples electrostatic waves (plasma oscillations) and electromagnetic waves i... more Any mechanism which couples electrostatic waves (plasma oscillations) and electromagnetic waves in a plasma will lead to radiation from plasma oscillations. The most important consequence of nonlinearity of the equations is that two electrostatic waves are coupled to one electromagnetic wave; this process is therefore responsible for radiation at the second harmonic (2ωp). Low-frequency or static inhomogeneities of the plasma couple one electrostatic wave to one electromagnetic wave, and therefore, produce radiation at (or near) the plasma frequency. Two types of inhomogeneity are considered: ``isotropic'' inhomogeneities, which are fluctuations in the plasma density, and ``anisotropic inhomogeneities,'' which comprise an inhomogeneous distribution of currents and magnetic fields. These radiation mechanisms are analyzed by means of a set of fluid equations for the electron component, which should provide an adequate description for plasma oscillations with wavenumbers small compared with the Debye wavenumber. The radiation field is evaluated by a Green function method, ignoring re-absorption, which one expects to be a very weak process. For each radiation mechanism, a formula is obtained for the volume emissivity of a turbulent plasma representing the plasma oscillations and the inhomogeneities each by a correlation function and an energy spectrum. Useful approximate forms of these formulas are given.
P HYSI CAL RK VI K%' LKTYKRS 10 eV which is about four times the unper-turbed mean electron therm... more P HYSI CAL RK VI K%' LKTYKRS 10 eV which is about four times the unper-turbed mean electron thermal energy (determined by a Langmuir probe). Thus the assumption of the cold plasma model is not unreasonable.
The method of expansion in instantaneous eigenfunctions is used to obtain approximate solutions t... more The method of expansion in instantaneous eigenfunctions is used to obtain approximate solutions to the linearized Vlasov equation when the unperturbed function is time‐dependent. The method is useful when the time‐dependence of the unperturbed function is slow compared with the plasma frequency. The general results are used to obtain the growth of wave energies in the quasilinear limitation of weak two‐stream instabilities. Deviations from previous results for this problem are found.
This is an informal report intended primarily for internal or traited external distribution. The ... more This is an informal report intended primarily for internal or traited external distribution. The opinions and conclusions, stated are those of (lie author and may or ma? not be those of the laboratory, H'onk performed wider (I* auspices ai the IS. Departme*! of Enere* b> the Lawrence Uvconor* Laboratory und\T Contract W-7-W5-Knp*4fl-MODEL FOR ION CONFINEMENT IN A HOT-ELECTRON TANDEM MIRROR ANCHOR ABSTRACT Anisotropic, hot electrons trapped in local minitnum-B wells have been proposed as MHD-stabilizing anchors to an otherwise axisyirniet-: c tandem configuration. This work describes a im^l for plasma confiner, >nt between the anchors and the remainder of the system and calculates the piwer loss implied by maintenance of this plasma.
The high‐frequency precessional mode of a hot‐electron‐stabilized magnetic configuration has prev... more The high‐frequency precessional mode of a hot‐electron‐stabilized magnetic configuration has previously been shown to be stable in a window of core‐plasma mass. Under conditions of frequency matching, the resulting stable negative‐energy precessional wave can be destabilized by coupling to positive‐energy shear‐Alfven waves. Coupling is avoided when the hot‐electron precession frequency exceeds the core‐plasma ion gyrofrequency.
This investigation is concerned with the development of a two-body distribution function in a pla... more This investigation is concerned with the development of a two-body distribution function in a plasma for use in a kinetic equation for the one-body distribution function. The kinetic equation is obtained for a uniform plasma for those circumstances in which the time dependence of higher-order distribution functions can be assumed to occur within a functional dependence on the one-particle distribution function. The conditions of validity for this functional-dependence assumption are discussed. The resulting interaction term is new in the sense that it contains no divergent integrals requiring cutoffs, and it may be considered accurate to first order in (e 2 /kTXD). The interaction term is composed of two parts. The first is a Boltzmann collision integral with a Debye-shielded interaction. The second term is due to the deviation of the shielding cloud from a Debye shield and is the Fokker-Planck form, the coefficients of which are finite and wellbehaved. Because of its form, with a convergent collision integral and convergent Fokker-Planck coefficients, the solution may be considered as a joining of the previous solutions to this problem.
As the amplitudes of the electron-plasma waves grow they scatter the beam electrons causing the n... more As the amplitudes of the electron-plasma waves grow they scatter the beam electrons causing the nonlinear instability to saturate and finally quench.
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Papers by David Baldwin