Hydromagnetic Waves and Instabilities Associated with Cometary Ion Pickup: ICE Observations (GRL 13(3) 1986)
Hydromagnetic Waves and Instabilities Associated with Cometary Ion Pickup: ICE Observations (GRL 13(3) 1986)
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DOI：
10.1029/gl013i003p00263
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发表时间：
1986-03
期刊：
影响因子：
--
通讯作者：
B. Tsurutani;E. Smith
中科院分区：
文献类型：
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作者：
B. Tsurutani;E. Smith
Giacobini-Zinner彗星周围的磁流体湍流具有两个主要成分：周期接近10² s的大振幅线偏振波和周期接近3 s的圆偏振波包。后者与长周期波产生的场强度变化有关。第三，通常观察到的功能被确定，包括磁场的部分旋转（钩状结构），这似乎也是由长周期波触发。研究了长周期波是由新电离的彗星中性粒子拾取产生的可能性。Wu和Davidson（1972）发现的共振不稳定性似乎能够解释水族彗星离子拾取的长周期波。理论的应用还表明，质子回旋波的增长率，作为氢离子拾取的结果，是有点低，由于更高的中性速度和更长的电离时间。波包和波钩的几个重要特征目前还无法解释，需要进一步研究。
The hydromagnetic turbulence surrounding comet Giacobini-Zinner is characterized by two dominent components: large amplitude, linearly polarized waves with periods near 10² s and circularly polarized wave packets with periods near 3 s. The latter appear in association with variations in field magnitude produced by the long period waves. A third, commonly observed feature is identified, consisting of a partial rotation of the magnetic field (a hook-like structure) which also appears to be triggered by the long period waves. The possibility that the long period waves are generated by the pickup of freshly ionized cometary neutrals has been investigated. A resonant instability identified by Wu and Davidson (1972) appears able to account for the long period waves in terms of the pickup of cometary ions of the water group. Application of the theory also indicates that the growth rate of proton cyclotron waves, as a consequence of hydrogen ion pickup, is somewhat lower, due to both higher neutral velocities and longer ionization times. Several significant features of the wave packets and hooks are presently unexplained and will require further study.