Investigation of lower hybrid wave damping in the PBX-M tokamak
- Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)
Lower hybrid (LH) current drive experiments on the Princeton Beta Experiment-Modified (PBX-M) [Phys. Fluids B {bold 2}, 1271 (1990)] have shown that the current profile can be changed by varying the phase velocity of the waves. The radial profile of the current carrying electrons was deduced from two-dimensional hard x-ray tomography. For a certain range of phase velocities, there is a correlation between the peak of the fast electron profile and the launched wave spectrum, despite the presence of a wide spectral gap between the phase velocity and the thermal electron energy distribution. A new model is proposed to explain how first-pass wave damping is possible in such plasmas. The rf power can form a tail of energetic electrons, and subsequently waves with moderate phase velocity can damp on them. For waves with very fast phase velocity, there must be an upshift of the n{sub {parallel}} spectrum for any damping to occur. These hypotheses are supported by ray tracing results which are coupled to relativistic Fokker{endash}Planck calculations of the electron distribution function. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 435175
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 1 Vol. 4; ISSN PHPAEN; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Investigation of lower hybrid wave damping
Experimental and theoretical investigation of local synergy between ion Bernstein and lower hybrid waves in the Princeton Beta Experiment{emdash}Modified
Accessibility for lower hybrid waves in PBX-M
Technical Report
·
Wed May 01 00:00:00 EDT 1996
·
OSTI ID:438529
Experimental and theoretical investigation of local synergy between ion Bernstein and lower hybrid waves in the Princeton Beta Experiment{emdash}Modified
Journal Article
·
Sun Feb 28 23:00:00 EST 1999
· Physics of Plasmas
·
OSTI ID:321496
Accessibility for lower hybrid waves in PBX-M
Technical Report
·
Thu Jul 01 00:00:00 EDT 1993
·
OSTI ID:10169809