Diamagnetic "bubble" equilibria in linear traps

Abstract

The plasma equilibrium in a linear trap at $\beta \approx 1$ (or above the mirror-instability threshold) under the topology-conservation constraint evolves into a kind of diamagnetic "bubble". This can take two forms: either the plasma body greatly expands in radius while containing the same magnetic flux, or, if the plasma radius is limited, the plasma distribution across flux-tubes changes, so that the same cross-section contains a greatly reduced flux. If the magnetic field of the trap is quasi-uniform around its minimum, the bubble can be made roughly cylindrical, with radius much larger than the radius of the corresponding vacuum flux-tube, and with non-paraxial ends. Then the effective mirror ratio of the diamagnetic trap becomes very large, but the cross-field transport increases. The confinement time can be found from solution of the system of equilibrium and transport equations and is shown to be ${\tau }_E\approx \sqrt{{\tau }_{\parallel }{\tau }_{\perp }}$. If the cross-field confinement is not too degraded by turbulence, this estimate in principle allows construction of relatively compact fusion reactors with lengths in the range of a few tens of meters. In many ways the described here diamagnetic confinement and the corresponding reactor parameters are similar to those claimed by the FRCs.

11 pages, 3 figures, will be submitted to Physics of Plasmas

References in corpus (1)

• Achievement of a record electron temperature for a magnetic mirror device

Cited by in corpus (8)

• On the structure of the boundary layer in a Beklemishev diamagnetic bubble
• RF plugging of multi-mirror machines
• Collisionless particle dynamic in an axi-symmetric diamagnetic trap
• Wall stabilization of the rigid ballooning $m=1$ mode in a long-thin mirror trap
• Rate equations model for multiple magnetic mirrors in various thermodynamic scenarios
• Evaluation of ambipolar potential barrier in the gas dynamic trap by Doppler spectroscopy
• Plasma Equilibrium in Diamagnetic Trap with Neutral Beam Injection
• Plugging of multi-mirror machines by a traveling rotating magnetic field