Tearing Modes In Reversed Field Pinch Research Articles

Influence of energetic ions on tearing modes in a reversed field pinch

Tearing mode stability analysis in the presence of circulating energetic ions (CEI) is studied in the reversed field pinch (RFP) magnetic configuration. In contrast to the minimal effect of precessional drift of CEI on tearing modes in tokamaks, the effect of precessional drift of CEI on tearing modes is important in the RFP. It is found that the effects of CEI on tearing modes in RFP depend on their toroidal circulating direction, and have a strong relation to the pressure gradient of CEI. For co-CEI, tearing modes can be stabilized if the pressure gradient of energetic ions is sufficiently large, which is qualitatively consistent with experimental results in the Madison Symmetric Torus.

Calculation of resistive magnetohydrodynamics and two-fluid tearing modes by example of reversed-field-pinch-like plasma

An algorithm suitable for numerical solution of linear eigenmode problems in resistive magnetohydrodynamics (MHD) and two-fluid MHD models without prior approximations is presented. For these plasma models, sets of equations suitable for numerical solution are derived and the details of the algorithm of this solution are given. The algorithm is general and is suitable for solution of boundary (eigenmode) problems for different plasma configurations. It is most effective, however, in one-dimensional models since the grid size has to be sufficiently small in order to resolve the tearing layer together with the scale of the size of the plasma. The technique is applied for solving for tearing eigenmodes in reversed field pinch (RFP) -like plasma in plane geometry. Results of resistive MHD and two-fluid models are compared in this case, showing that the two-fluid effects on tearing modes in RFPs are sizable.