Suppression of small scale dynamo action by an imposed magnetic field.
Suppression of small scale dynamo action by an imposed magnetic field.
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通过施加磁场抑制小规模发电机作用。
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
A. Brandenburg
中科院分区：
文献类型：
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作者：
N. Haugen;A. Brandenburg
采用直接数值模拟的方法研究了外加磁场作用下的非螺旋流体磁流体湍流。结果表明，外加磁场降低了惯性范围内的光谱磁能。这是因为小型发电机受到了抑制。然而，在大尺度上，对于中等强度的场，谱磁能随着外加磁场强度的增加而增加，而对于更强的场，谱磁能仅略有降低。通过监测一点磁场和速度的演化，明确证实了Alfve n波的存在。频率omega与v(A)k(1)一致，其中v(A)是Alfve n速度，k(1)是盒子中的最小波数。
Nonhelical hydromagnetic turbulence with an externally imposed magnetic field is investigated using direct numerical simulations. It is shown that the imposed magnetic field lowers the spectral magnetic energy in the inertial range. This is explained by a suppression of the small scale dynamo. At large scales, however, the spectral magnetic energy increases with increasing imposed field strength for moderately strong fields, and decreases only slightly for even stronger fields. The presence of Alfve n waves is explicitly confirmed by monitoring the evolution of magnetic field and velocity at one point. The frequency omega agrees with v(A) k(1) , where v(A) is the Alfve n speed and k(1) is the smallest wave number in the box.