Plasma losses through an adiabatic cusp

Journal Article · Fri Feb 01 04:00:00 EDT 1974 · J. Plasma Phys., v. 11, pp. 77-91

DOI:https://doi.org/10.1017/S002237780002448X· OSTI ID:4352294

Kaye, A S

Previous calculations of lambda = 1 cusp losses were extended to the case where there exists a third adiabatic'' invariant of the particle motion, related to the magnetic moment, and additional to the particle energy and angular momentum. Simple analytic results were obtained for the particle and energy loss rate from a Maxwellian plasma in both plane and axisymmetric geometry, electric fields being assumed zero everywhere. The results were valid for a plasma radius large relative to the ion gyro-radius, in which case the adiabaticity in the sense used reduced the loss rate by a factor 2/3 lambda /sup 1/2/, to give an overall scaling as lambda /sup -3/2/ with externa l mirror ratio lambda . The absolute value was about a factor two less than the previously accepted result (for lambda = 1 only) for an axisymmetric cusp. The enhanced scaling with lambda arose from the absence of a certain class of particles in the sheath, which must be everywhere adiabatic; its applicability to a simple theta pinch was queried, however. The end loss rate of angular momentum was also obtained, and was non-zero at a point cusp. This was shown to lead to rapid rotational instability in a collisionless theta pinch. (auth)

• Research Organization: Queen's Univ., Belfast
• NSA Number: NSA-29-025712
• OSTI ID: 4352294
• Journal Information: J. Plasma Phys., v. 11, pp. 77-91, Journal Name: J. Plasma Phys., v. 11, pp. 77-91; ISSN JPLPB
• Country of Publication: United Kingdom
• Language: English

Related Subjects

*COLLISIONLESS PLASMA-- CONFINEMENT
*CUSPED GEOMETRIES-- ENERGY LOSSES
ADIABATIC PROCESSES
LOSSES
N70100* --Physics--Controlled Thermonuclear Research-- Confinement & Heating
NEUTRAL PARTICLES
PLASMA INSTABILITY
ROTATION
THETA PINCH