Effect of nonuniform resistivity in Petschek reconnection
Effect of nonuniform resistivity in Petschek reconnection
复制标题
Petschek 重联中非均匀电阻率的影响
DOI：
--
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
T. Forbes
中科院分区：
文献类型：
--
作者：
H. Baty;E. Priest;T. Forbes
利用二维含时磁流体动力学模拟方法，研究了在均匀电阻率下稳态磁场重联中Petschek解的存在性这一有争议的问题.一个经典的局部非均匀电阻率的轮廓是指数下降，从X点是有帮助的设置Petschek解决方案作为第一步，使用超指定的边界条件的程序。然后研究了以各种方式改变电阻率剖面的响应。结果表明，当采用准均匀电阻率时，可以得到Petschek组态。如果电阻率剖面在接近X点处呈现弱的负梯度，则会出现这种情况，这主导了固有的数值贡献;否则会出现不稳定性，从而破坏配置。一个真正均匀的电阻率可能只是在边缘上稳定。最后，对Kulsrud [Earth Planets Space 53，417（2001）]关于“不存在”的论证进行了验证。
The controversial topic of the existence of a Petschek solution in steady-state magnetic reconnection for a uniform resistivity is investigated, by using two-dimensional time-dependent magnetohydrodynamic simulations. A classical localized nonuniform resistivity with a profile that is exponentially decreasing from the X point is helpful to set up the Petschek solution as a first step, using a procedure with overspecified boundary conditions. The response to changing the resistivity profile in various ways is then studied. It is found that a Petschek configuration is obtained when a quasiuniform resistivity is adopted. This is the case if the resistivity profile exhibits a weak negative gradient close to the X point, which dominates an inherent numerical contribution; otherwise an instability develops which disrupts the configuration. A truly uniform resistivity is probably only marginally stable. Finally, the validity of the arguments given by Kulsrud [Earth Planets Space 53, 417 (2001)] about the “incorr...