Discovery of Soft X-Ray Emission from Io, Europa, and the Io Plasma Torus
Discovery of Soft X-Ray Emission from Io, Europa, and the Io Plasma Torus
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发现木卫一、木卫二和木卫一等离子体环发射的软 X 射线
DOI：
10.1086/340434
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
M. Weisskopf
中科院分区：
文献类型：
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作者：
R. Elsner;G. Gladstone;J. Waite;F. Crary;R. Howell;Robert E. Johnson;P. Ford;A. Metzger;K. Hurley;E. Feigelson;G. Garmire;A. Bhardwaj;D. Grodent;T. Majeed;A. Tennant;M. Weisskopf
我们报告了在伽利略卫星木卫一和木卫二（可能是木卫三）以及木卫一等离子体环（IPT）上发现的软（0.25-2 keV） x射线发射。来自IPT区域的高能（大于10 keV）氢、氧和硫离子轰击似乎是伽利略卫星x射线发射的可能来源。根据我们的估计，由太阳x射线激发的荧光x射线发射，即使是在活跃太阳的耀斑期间，电荷交换过程，以前被用来解释木星的x射线极光和彗星的x射线发射，以及尘埃颗粒的离子剥离，都不能解释观测到的发射。另一方面，几百至几千eV范围内的非热电子的软x射线轫致辐射可能占IPT观测到的x射线通量的很大一部分。
We report the discovery of soft (0.25-2 keV) X-ray emission from the Galilean satellites Io and Europa, probably Ganymede, and from the Io Plasma Torus (IPT). Bombardment by energetic (greater than 10 keV) H, O, and S ions from the region of the IPT seems to be the likely source of the X-ray emission from the Galilean satellites. According to our estimates, fluorescent X-ray emission excited by solar X-rays, even during flares from the active Sun, charge-exchange processes, previously invoked to explain Jupiter's X-ray aurora and cometary X-ray emission, and ion stripping by dust grains fail to account for the observed emission. On the other hand, bremsstrahlung emission of soft X-rays from nonthermal electrons in the few hundred to few thousand eV range may account for a substantial fraction of the observed X-ray flux from the IPT.