Investigation of lower hybrid wave damping

Technical Report · Wed May 01 04:00:00 EDT 1996

OSTI ID:438529

Bernabei, S; Ignat, D; Kaita, R; Okabayashi, M; von Goeler, S ^[1]; Cardinali, A ^[2]; Giruzzi, G; Hoang, G T ^[3]; Paoletti, F ^[4]

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1. Princeton Univ., NJ (United States). Plasma Physics Lab.
2. Associazione EURATOM-ENEA sulla Fusione, Frascati (Italy)
3. Association Euratom-CEA, Centre d`Etudes Nucleaires de Cadarache, 13 - Saint-Paul-lez-Durance (France)
4. Via dei Provoletti, Tor Bella Passera, Rome (Italy)

Lower Hybrid (LH) current drive experiments on PBX-M 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 2-D 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. A model is proposed to explain how first-pass damping is possible in such plasmas. The radio frequency (RF) power can form a tail of energetic electrons, and waves with moderate phase velocity can damp on them. For waves with very fast phase velocity, there must be an upshift of the n-spectrum for any damping to occur. These hypotheses are supported by ray tracing results which were coupled to relativistic Fokker-Planck calculations of the electron distribution function.

• Research Organization: Princeton Univ., NJ (United States). Plasma Physics Lab.
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 438529
• Report Number(s): PPPL--3195; ON: DE97002428
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DAMPING
EFFICIENCY
GREEN FUNCTION
LOWER HYBRID CURRENT DRIVE
MAGNETIC FIELD CONFIGURATIONS
PBX DEVICES
PHOTON COMPUTED TOMOGRAPHY