The fate of sub-micron circumplanetary dust grains I: Aligned dipolar magnetic fields
- 作者：Daniel Jontof-Hutter ; danielj@astro.umd.edu ; Douglas P. Hamilton
- 关键词：Planetary rings ; Jupiter ; Rings ; Magnetic fields ; Saturn ; Rings
- 刊名：Icarus
- 出版年：2012
- 期刊代码：90_00191035
- 类别：ph
- 出版时间：March, 2012
- 卷：218
- 期：1
- 页码：420-432
- 文件大小：1237 K
摘要
We study the stability of charged dust grains orbiting a planet and subject to gravity and the electromagnetic force. Our numerical models cover a broad range of launch distances from the planetary surface to beyond synchronous orbit, and the full range of charge-to-mass ratios from ions to rocks. Treating the spinning planetary magnetic field as an aligned dipole, we map regions of radial and vertical instability where dust grains are driven to escape or crash into the planet. We derive the boundaries between stable and unstable trajectories analytically, and apply our models to Jupiter, Saturn and the Earth, whose magnetic fields are reasonably well represented by aligned dipoles.