Experimental observation of microwave absorption and electron heating due to the two plasmon decay instability and resonance absorption

Thesis/Dissertation · Thu Jan 01 00:00:00 EST 1981

OSTI ID:6692566

Rasmussen, D A

The interaction of intense microwaves with an inhomogeneous plasma is studied in two experimental devices. In the first device an investigation was made of microwave absorption and electron heating due to the parametric decay of microwaves into electron plasma waves (Two Plasmon Decay instability, TPDI), modeling a process which can occur near the quarter critical surface in laser driven pellets. P-polarized microwave (f = 1.2 GHz, P/sub 0/ less than or equal to 12 kW) are applied to an essentially collisionless, inhomogeneous plasma, in an oversized waveguide, in the U.C. Davis Prometheus III device. The initial density scale length near the quarter critical surface is quite long (L/lambda/sub De/ approx. = 3000 or k/sub 0/L approx. = 15). The observed threshold power for the TPDI is quite low (P/sub T/approx. = 0.1 kW or v/sub os//v/sub e/ approx. = 0.1). Near the threshold the decay waves only occur near the quarter critical surface. As the incident power is increased above threshold, the decay waves spread to lower densities, and for P/sub 0/ greater than or equal to lkW, (v/sub os//v/sub e/ greater than or equal to 0.3) suprathermal electron heating is strong for high powers (T/sub H/ less than or equal to 12 T/sub e/ for P/sub 0/ less than or equal to 8 kW or v/sub os//v/sub e/ less than or equal to 0.9).

• OSTI ID: 6692566
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
INHOMOGENEOUS PLASMA
MICROWAVE RADIATION
RESONANCE ABSORPTION
ABSORPTION
DECAY INSTABILITY
ELECTRON TEMPERATURE
ELECTROMAGNETIC RADIATION
INSTABILITY
PLASMA
PLASMA INSTABILITY
RADIATIONS
700101* - Fusion Energy- Plasma Research- Confinement
Heating
& Production