Electron ripple injection concept for transport control

Conference · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7011242

Choe, W; Ono, M; Hwang, Y S

Recent experiments in many devices have provided firm evidence that the edge radial electric field profile differs between L- and H-modes, and that these fields can greatly modify transport in tokamak plasmas. A nonintrusive method for inducing radial electric field based on electron ripple injection is being developed by the CDX-U group. This technique utilizes a pair of special coils to create a local magnetic field ripple to trap the electrons at the edge of the plasma. The trapped electrons then drift into the plasma due to the [del]B drift. An ECH power is applied to accelerate electrons to sufficient perpendicular energy to penetrate into the plasma. Application of ECH power to the trapped electrons should provide the desired 20 A of electron current with electrons of a few keV of energy and v[perpendicular]/v[parallel] [much gt] 1. A controlled experiment to investigate the physics of ECH aided ripple injection has been designed on CDX-U. With the set of ripple coils designed for CDX-U, a ripple fraction of [delta] ([double bond] [del]B/B[sub av]) [approximately] 5% is attainable. At this ripple fraction, electrons are trapped if v[perpendicular]/v[parallel] [much gt] 1> (2[delta])[sup [minus][1/2]] [approx]3. A resonant cavity box was fabricated for efficient heating of the trapped electrons. It is also capable of measuring the effect of the field ripple in conjunction with trapped electrons. Some preliminary results are given.

• Research Organization: Princeton Univ., NJ (United States). Plasma Physics Lab.
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 7011242
• Report Number(s): PPPL-CFP-2757; CONF-9209181--3; ON: DE93002103
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700310* -- Plasma Confinement-- (1992-)
700330 -- Plasma Kinetics
Transport
& Impurities-- (1992-)
BEAM INJECTION
CHARGED-PARTICLE TRANSPORT
CLOSED PLASMA DEVICES
CONFINEMENT
ECR HEATING
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
H-MODE PLASMA CONFINEMENT
HEATING
HIGH-FREQUENCY HEATING
LEPTONS
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC FIELD RIPPLES
PLASMA CONFINEMENT
PLASMA HEATING
RADIATION TRANSPORT
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRAPPED ELECTRONS