A model of force balance in Jupiter's magnetodisc including hot plasma pressure anisotropy
A model of force balance in Jupiter's magnetodisc including hot plasma pressure anisotropy
复制标题
木星磁盘中的力平衡模型，包括热等离子体压力各向异性
DOI：
--
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
S. Cowley
中科院分区：
文献类型：
--
作者：
J. Nichols;N. Achilleos;S. Cowley
我们提出了一个包括热等离子体压力各向异性影响的木星磁碟力平衡的迭代矢量势模型。该基准模型在整个径向范围内产生的结果与伽利略磁场和等离子体数据一致。热等离子体压力梯度和离心力分别在向内~ 20 RJ和向外~ 50 RJ区域占主导地位，而对于压力各向异性的实际值，各向异性电流要么是主导成分，要么至少与两者之间区域的热等离子体压力梯度电流相当。考虑到热等离子体压力的各向异性，在观测到的热等离子体参数Kh（热压力和单位通量管体积的乘积）的变化范围内，主椭圆和木卫三足迹的纬度分别发生了~ 1.2°和~ 2.7°的变化，这与在极光图像中观测到的变化相当。然而，中磁层容易受到火水带不稳定性的影响，对于Kh=2.0−2.5 × 107 Pa m T−1，其赤道峰值βh∥e - βh⊥≃1−2。对于较大的Kh值，βh∥e - βh⊥在~ 25 RJ附近超过2，模型不收敛。这表明，小规模等离子体释放或“细雨”等离子体可能经常发生在中磁层，从而形成了木星等离子体质量损失的重要模式。
We present an iterative vector potential model of force balance in Jupiter's magnetodisc that includes the effects of hot plasma pressure anisotropy. The fiducial model produces results that are consistent with Galileo magnetic field and plasma data over the whole radial range of the model. The hot plasma pressure gradient and centrifugal forces dominate in the regions inward of ∼20 RJ and outward of ∼50 RJ, respectively, while for realistic values of the pressure anisotropy, the anisotropy current is either the dominant component or at least comparable with the hot plasma pressure gradient current in the region in between. With the inclusion of hot plasma pressure anisotropy, the ∼1.2 and ∼2.7° shifts in the latitudes of the main oval and Ganymede footprint, respectively, associated with variations over the observed range of the hot plasma parameter Kh, which is the product of hot pressure and unit flux tube volume, are comparable to the shifts observed in auroral images. However, the middle magnetosphere is susceptible to the firehose instability, with peak equatorial values of βh∥e−βh⊥e≃1 − 2, for Kh=2.0 − 2.5 × 107 Pa m T−1. For larger values of Kh,βh∥e−βh⊥e exceeds 2 near ∼25 RJ and the model does not converge. This suggests that small‐scale plasmoid release or “drizzle” of iogenic plasma may often occur in the middle magnetosphere, thus forming a significant mode of plasma mass loss, alongside plasmoids, at Jupiter.
土星磁盘中的力平衡模型
DOI：
10.1111/j.1365-2966.2009.15865.x
发表时间：
2010
影响因子：
4.8
作者：
Achilleos N
通讯作者：
Achilleos N