A pulsating auroral X-ray hot spot on Jupiter
A pulsating auroral X-ray hot spot on Jupiter
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DOI：
10.1038/4151000a
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发表时间：
2002-02-28
期刊：
影响因子：
64.8
通讯作者：
Cravens, TE
中科院分区：
文献类型：
--
作者：
Gladstone, GR;Waite, JH;Cravens, TE
木星的 X 射线极光被认为是由从内磁层沉淀到木星极地区域的高能硫离子和氧离子激发的(1-3)。在这里，我们报告的高空间分辨率观测结果表明，木星的大部分北极极光 X 射线来自一个“热点”，该“热点”位于与内磁层相连的纬度的极地位置。该热点似乎固定在磁纬度和经度上，并且发生在还观察到异常红外线（4-7）和紫外线（8）发射的区域。我们从数据推断，激发极光的粒子起源于外磁层。热点 X 射线的脉动周期约为 45 分钟，该周期与近木星航天器观测到的高纬度射电和高能电子爆发的周期相似(9,10)。这些结果否定了木星极光 X 射线发射主要是由内磁层高能重离子的稳定沉淀激发的观点。相反，X射线似乎是由外磁层中目前无法解释的过程产生的，该过程在极宽的波长范围内产生高度局部化和高度可变的发射。
Jupiter's X-ray aurora has been thought to be excited by energetic sulphur and oxygen ions precipitating from the inner magnetosphere into the planet's polar regions(1-3). Here we report high-spatial-resolution observations that demonstrate that most of Jupiter's northern auroral X-rays come from a 'hot spot' located significantly poleward of the latitudes connected to the inner magnetosphere. The hot spot seems to be fixed in magnetic latitude and longitude and occurs in a region where anomalous infrared(4-7) and ultraviolet(8) emissions have also been observed. We infer from the data that the particles that excite the aurora originate in the outer magnetosphere. The hot spot X-rays pulsate with an approximately 45-min period, a period similar to that reported for high-latitude radio and energetic electron bursts observed by near-Jupiter spacecraft(9,10). These results invalidate the idea that jovian auroral X-ray emissions are mainly excited by steady precipitation of energetic heavy ions from the inner magnetosphere. Instead, the X-rays seem to result from currently unexplained processes in the outer magnetosphere that produce highly localized and highly variable emissions over an extremely wide range of wavelengths.