Spontaneous Generation of the Magnetic Field and Suppression of the Heat Conduction in Cold Fronts
Spontaneous Generation of the Magnetic Field and Suppression of the Heat Conduction in Cold Fronts
复制标题
冷锋中磁场的自发产生和热传导的抑制
DOI：
10.1086/379309
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
M. Hattori
中科院分区：
文献类型：
--
作者：
N. Okabe;M. Hattori
我们已经确定的物理机制负责等离子体不稳定性，这是第一次发现的Ramani和拉瓦尔在1978年，与各向异性的速度分布诱导的温度梯度，其中有增长的低频横向磁波，即使在没有背景磁场。我们已经表明，负责增长的模式之一的物理机制是相同的韦伯不稳定性。通过考虑波粒相互作用，给出了不稳定性的非线性饱和水平。对饱和后磁场的非线性演化进行了推测，并将结果应用于钱德拉X射线天文台新发现的星系团冷锋。我们预测在冷锋的整个区域内存在一个约10 μG的磁场，该磁场与表面相切，并且热传导被所产生的磁场捕获的电子显着抑制。这种不稳定性可能为宇宙磁场的起源提供新的可能性。
We have determined the physical mechanism responsible for plasma instabilities, which were first found by Ramani & Laval in 1978, associated with anisotropic velocity distributions induced by a temperature gradient in which there are growing low-frequency transverse magnetic waves, even in the absence of background magnetic fields. We have shown that the physical mechanism responsible for the growth of one of the modes is identical to the Weibel instability. The nonlinear saturation level of the instability is also provided by considering the wave-particle interactions. The nonlinear evolution of the magnetic fields after the saturation is speculated on. The results are applied to the cold fronts newly discovered by the Chandra X-Ray Observatory in clusters of galaxies. We predict the existence of a magnetic field of ~10 μG tangential to the surface over the entire region of the cold front and that the heat conduction is significantly suppressed by the trapping of electrons by the generated magnetic fields. The instability may provide a new possibility for the origin of the cosmic magnetic field.