No abstract available

No abstract available

[en] It is shown from quasilinear theory that an initially isotropic magnetized plasma will be forced into an anisotropic state in ion-cyclotron resonance heating. Strong heating of perpendicular ion temperature and strong cooling of longitudinal temperature should occur simultaneously. The maximum temperature ratio predicted by quasilinear theory is in exact agreement with that predicted from basic thermodynamic arguments by Busnardo--Neto, Dawson, Kamimura and Lin. Heating by fast hydromagnetic wave is also examined

No abstract available

[en] At the Lawrence Berkeley National Laboratory we are constructing an ECR ion source test facility for nuclear science as well as industrial applications experiments. For these purposes, a single-stage 2.45 GHz electron cyclotron resonance ion source has been designed and constructed. It features an axial magnetic field with a mirror ratio of up to six and a hexapole field produced by a simple Nd endash Fe endash B permanent magnet assembly. In order to enhance the ion confinement time, the source plasma volume has been enlarged as much as possible while still maintaining a high mirror ratio. This paper describes the design of the ion source, the extraction system and the test stand. First, operational experience and experimental results with an argon discharge are presented. copyright 1998 American Institute of Physics

[en] The hot-electron plasma produced by resonant electron cyclotron heating was successfully used as a well-controlled initial phase for a subsequent slow compression experiment. The plasma electron temperature increased almost linearally with an increase of magnetic field up to a compression ratio of over 10:1. The initial value was about 10 keV, and the final value was about 110 keV. An important observation was that the compressed plasma appeared to be stable, even when the cold background plasma density decreased dramatically

[en] We have investigated, via a 1--2/2 dimensional computer simulation, the possibility of forcing an initially isotropic, magnetized plasma into an anisotropic state by means of an external pump. Strong heating of the perpendicular ion temperature was observed together with a strong cooling of the longitudinal temperature. This mechanism could enhance particle trapping in tokamaks and increase confinement time in mirror machines. We use basic physical arguments to predict the maximum temperature ratio that can be obtained

[en] The absorption of the extraordinary mode at frequencies downshifted with respect to either the fundamental or the second harmonic electron cyclotron resonance and such that the relevant resonance lies outside the plasma is evaluated for a Maxwellian distribution with a current-carrying superthermal tail. The contribution from the current-carrying electrons to the absorption is obtained by Lorentz-transforming the dielectric tensor from the comoving to the laboratory frame. The dielectric tensor accounts for the fully relativistic cyclotron resonance condition and the corresponding Hermitian part includes the relevant thermal effects. The spatial dependence of the drift momentum, the density, and the temperature of both the bulk and the superthermals is accounted for in the evaluation of the absorption profile. The relevance of the relativistic effects is discussed with respect to both the profile of the absorption and the overall absorption

[en] In 1981 the research activities have been continued in the central fields wave- and plasma heating, high-voltage belt-pinch, laser applications and plasma focus. The activities in the first three subjects have been coordinated, as in the past with the research program of the Max-Planck-Institut fuer Plasmaphysik (IPP) in Garching. The projects 'wave- and plasma heating' and 'high-voltage belt-pinch' terminated as scheduled at the end of 1981 and have been replaced by the new project electron-cyclotron-resonance heating (ECRH). The experiments supported by DFG of the plasma focus project have been performed in close cooperation with research groups in Heidelberg, Darmstadt and Duesseldorf. (orig.)

[en] Probe arrays used to measure transient radio-frequency impedance in ion cyclotron resonance heating experiments often give erroneous results. This problem is analyzed and the results are given. A system composed of directional couplers and four probes is proposed to improve the accuracy of the measurements