Radiative instabilities in a sheared magnetic field
作者:
J. F. Drake,
L. Sparks,
G. Van Hoven,
期刊:
Physics of Fluids(00319171)
(AIP Available online 1988)
卷期:
Volume 31,
issue 4
页码: 813-822
ISSN:0031-9171
年代: 1988
DOI:10.1063/1.866817
出版商: AIP
数据来源: AIP
摘要:
The structure and growth rate of the radiative instability in a sheared magnetic fieldBhave been calculated analytically using the Braginskii fluid equations. In a shear layer, temperature and density perturbations are linked by the propagation of sound waves parallel to the local magnetic field. As a consequence, density clumping or condensation plays an important role in driving the instability. Parallel thermal conduction localizes the mode to a narrow layer wherek∥=k⋅B/‖B‖ is small and stabilizes short wavelengthsk>kc, wherekcdepends on the local radiation and conduction rates. Thermal coupling to ions also limits the width of the unstable spectrum. It is shown that a broad spectrum of modes is typically unstable in tokamak edge plasmas and it is argued that this instability is sufficiently robust to drive the large‐amplitude density fluctuations often measured there.
点击下载:
PDF
(1025KB)
返 回