Advances in spheromak understanding and parameters

Conference · Mon Jan 01 00:00:00 EST 1990

OSTI ID:7185702

Fernandez, J C

A spheromak is a toroidally-shaped magnetized plasma configuration in which no material links the torus so that the topology of the spheromak boundary is spherical. The magnetic fields in the plasma are generated by the internal plasma currents. In the period of ten years since the properties of a nearly force-free spheromak configuration were described using single-fluid MHD theory, remarkable theoretical and experimental advances have been made. This paper highlights some of that work. Spheromak not only have been successfully produced in the laboratory using a variety of methods, but also translated, compressed and stably sustained for many resistive-decay times. Spheromak formation, equilibrium and stability to current-driven modes have been successfully modeled by single-fluid MHD coupled with the concepts of magnetic helicity and relaxation toward the minimum-energy force-free state. There is evidence, however, that the relaxation mechanism which drives parallel plasma currents is due to effects beyond the scope of single-fluid resistive MHD. The confinement properties of clean spheromaks have been measured, and shown to be excellent, provided the fraction of open magnetic flux at the edge is decreased sufficiently. It has been shown theoretically how plasma {l angle}{beta}{r angle}{sub vol} limits of {approx}10% can be obtained by properly shaping either the conducting wall geometry or the spheromak current profile. In addition to studies directly relating to fusion, the use of spheromaks for other goals is briefly described, including tokamak refueling, radiation production, magnetically-insulted inertially confined fusion, demonstration of helicity injection by mechanical means, and energy storage/transfer to accelerate fast metallic projectiles.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 7185702
• Report Number(s): LA-UR-90-1820; CONF-900739-1; ON: DE90012052; TRN: 90-016482
• Resource Relation: Conference: 4. Latin American workshop on plasma physics, Buenos Aires (Argentina), 16-27 Jul 1990
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
SPHEROMAK DEVICES
PLASMA CONFINEMENT
EQUILIBRIUM
MAGNETIC CONFINEMENT
MAGNETIC FIELDS
PLASMA INSTABILITY
CLOSED PLASMA DEVICES
CONFINEMENT
INSTABILITY
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
700101* - Fusion Energy- Plasma Research- Confinement
Heating
& Production