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Vlasov fluid stability of a skin current Z pinch with finite electron pressure

Journal Article · · Physics of Fluids B; (USA)
DOI:https://doi.org/10.1063/1.859806· OSTI ID:5838189
 [1]
  1. The Blackett Laboratory, Imperial College, London SW7 2BZ, United Kingdom (GB)

The linear stability of a Z-pinch confined by a skin current has been studied in the collisionless regime using the Vlasov fluid model for arbitrary {ital m} number. The trajectory integrals that are normally so formidable an aspect of Vlasov fluid analyses are greatly simplified in this equilibrium and the eigenvalue equation reduces to a dispersion relation derived from the plasma edge boundary condition. For the case {ital T}{sub {ital e}}=0, an analytic solution is found in the short-wavelength limit for the growth rate, which saturates for all {ital m} at a value of {pi}{sup 1/2}{ital v}{sub {ital T}}/2{ital a}, where {ital v}{sub {ital T}} is the ion thermal velocity and {ital a} is the pinch radius. This should be compared with the ideal magnetohydrodynamic (MHD) growth rate for the same equilibrium that increases without limit as {ital k}{sup 1/2}, where {ital k} is the axial wave number. The solution with finite electron temperature is achieved by a Neumann series expansion, which is shown to converge for all finite values of {Gamma}, the ratio of specific heats. In the short-wavelength limit with {ital T}{sub {ital e}}={ital T}{sub {ital i}}, the growth rates are double those for cold electrons. The deviation from this factor of two increase is always less than 10% for longer wavelengths.

OSTI ID:
5838189
Journal Information:
Physics of Fluids B; (USA), Journal Name: Physics of Fluids B; (USA) Vol. 3:5; ISSN 0899-8221; ISSN PFBPE
Country of Publication:
United States
Language:
English