Feedback stabilization of plasma instabilities using a modulated ion beam

Journal Article · Thu Oct 01 04:00:00 EDT 1992 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860416· OSTI ID:7250401

Tham, P; Sen, A K ^[1]

---

1. Department of Electrical Engineering and Plasma Physics Laboratory, Columbia University, New York, New York 10027 (United States)

A new technique for feedback suppression using a modulated ion beam as a remote suppressor has been developed for the first time. A Langmuir probe was used as the sensor. The feedback loop was completed with a phase shifter and amplifiers. This technique was demonstrated by stabilizing the collisionless, curvature-driven trapped particle instability down to a baseline noise level with an appropriate feedback gain and phase. An important feature is that the injected ion beam is nonperturbing to the plasma, constituting only 1% of the plasma density. A simple theory to describe the experimental results is presented and its predictions show generally good agreement with the experiment. To indicate that this concept could also be extended to other plasma instabilities, the rotationally driven {bold E}{times}{bold B} mode was also stabilized. Since the basic mechanism of suppression is the cancellation of charge separation inherent in an instability, a modulated electron beam performed equally well. Such remote, nonperturbing particle beam suppressors have great potential for remote suppression of plasma instabilities in a variety of plasma devices.

• DOE Contract Number: FG02-86ER53218
• OSTI ID: 7250401
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 4:10; ISSN 0899-8221; ISSN PFBPE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
700370 -- Plasma Fluid & MHD Properties-- (1992-)
ANNULAR SPACE
BALLOONING INSTABILITY
CLOSED CONFIGURATIONS
CLOSED PLASMA DEVICES
CONFIGURATION
CONFINEMENT
EQUILIBRIUM
INSTABILITY
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC ISLANDS
MHD EQUILIBRIUM
PLASMA CONFINEMENT
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PRESSURE GRADIENTS
SPACE
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TOROIDAL CONFIGURATION