Accessibility for lower hybrid waves in PBX-M

Technical Report · Thu Jul 01 04:00:00 EDT 1993

DOI:https://doi.org/10.2172/10169809· OSTI ID:10169809

Takahashi, H; Bell, R; Bernabei, S; Chance, M; Chu, T K; Gettelfinger, G; Greenough, N; Hatcher, R; Ignat, D; Jardin, S; Kaita, R; Kaye, S; Kugel, H; LeBlanc, B; Manickam, J; Okabayashi, M; Ono, M; Paul, S; Perkins, F; Sauthoff, N ; Sesnic, S; Sun, Y; Tighe, W; Valeo, E; von Goeler, S ^[1]; Batha, S; Levinton, F ^[2]; Dunlap, J; England, A; Harris, J; Hirshman, S; Isler, R; Post-Zwicker, A ^[3]; Jones, S; Kesner, J; Luckhardt, S; Paoletti, F ^[4]; Schmitz, L; Tynan, G ^[5]

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1. Princeton Univ., NJ (US). Plasma Physics Lab.
2. Fusion Physics and Technology, Torrance, CA (US)
3. Oak Ridge National Lab., TN (US)
4. Massachusetts Inst. of Tech., Cambridge, MA (US)
5. Univ. of California, Los Angeles, CA (US)

Understanding the wave damping mechanism in the presence of a `spectral gap` is an important issue for the current profile control using Lower Hybrid Current Drive (LHCD). The authors examine a traditional explanation based upon upshifting of the wave parallel refractive index (n{sub {parallel}}) and find that there can be an upper bound in the n{sub {parallel}} upshift. The amount of upshift is not sufficient to bridge the spectral gap completely under some PBX-M LHCD conditions. There is experimental evidence, however, that current was driven even under such conditions. Another mechanism is also considered, based upon the 2-D velocity space dynamics coupled with a compound wave spectrum, here consisting of forward- and backward-running waves. The runaway critical speed relative to the phase speeds of these waves plays an important role in this model.

• Research Organization: Princeton Univ., NJ (United States). Plasma Physics Lab.
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 10169809
• Report Number(s): PPPL--2920; ON: DE93017513
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340
700350
DAMPING
ELECTRON DRIFT
ELECTRONS
EXPERIMENTAL DATA
HYBRID RESONANCE
LIMITING VALUES
LOWER HYBRID CURRENT DRIVE
LOWER HYBRID HEATING
OPERATION
PBX DEVICES
PHASE VELOCITY
PLASMA PRODUCTION, HEATING, CURRENT DRIVE, AND INTERACTIONS
PLASMA WAVES
PLASMA WAVES, OSCILLATIONS, AND INSTABILITIES
REFRACTIVE INDEX
WAVE FORMS