部分电离日珥等离子体中的耗散不稳定性
Dissipative instability in partially ionised prominence plasmas
摘要：
我们调查的性质耗散不稳定的边界（这里看到的切向不连续）之间的粘性日冕和部分电离的突出等离子体在不可压缩的限制。的部分电离的重要性进行了研究的电离分数。匹配的解决方案的速度和总压力的横向分量在日珥和日冕等离子体之间的接口，我们推导出一个色散关系，其虚部描述的不稳定性的演变。结果在弱耗散极限下得到。使用简单的分析方法，我们表明，耗散不稳定性出现低于开尔文-亥姆霍兹不稳定阈值的流速。虽然粘度倾向于使等离子体不稳定，但部分电离（通过考林电阻率）的效果将起到稳定界面的作用。对于更接近中性气体的电离度，对于更大的平衡流量值，界面将不稳定。在研究双折射和暗羽流之间界面的不稳定现象时，也采用了同样的原理。在这种情况下出现的不稳定模式有一个非常小的增长率和耗散不稳定性不能解释羽流的外观。本研究提高了我们的理解的复杂性的动力学过程在太阳能电池和太阳日冕的接口，部分电离的作用可以对等离子体的稳定性。我们的研究结果清楚地表明，部分电离的问题引入了新的方面的等离子体的稳定性与后果的演变的太阳能电池。
英文摘要：
We investigate the nature of dissipative instability at the boundary (seen here as tangential discontinuity) between the viscous corona and the partially ionised prominence plasma in the incompressible limit. The importance of the partial ionisation is investigated in terms of the ionisation fraction. Matching the solutions for the transversal component of the velocity and total pressure at the interface between the prominence and coronal plasmas, we derive a dispersion relation whose imaginary part describes the evolution of the instability. Results are obtained in the limit of weak dissipation. Using simple analytical methods, we show that dissipative instabilities appear for flow speeds that are lower than the Kelvin-Helmholtz instability threshold. While viscosity tends to destabilise the plasma, the effect of partial ionisation (through the Cowling resistivity) will act towards stabilising the interface. For ionisation degrees closer to a neutral gas the interface will be unstable for larger values of equilibrium flow. The same principle is assumed when studying the appearance of instability at the interface between prominences and dark plumes. The unstable mode appearing in this case has a very small growth rate and dissipative instability cannot explain the appearance of flows in plumes. The present study improves our understanding of the complexity of dynamical processes at the interface of solar prominences and solar corona, and the role partial ionisation can have on the stability of the plasma. Our results clearly show that the problem of partial ionisation introduces new aspects of plasma stability with consequences on the evolution of solar prominences.
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