Complex structure within Saturn’s infrared aurora
Complex structure within Saturn’s infrared aurora
复制标题
土星红外极光内的复杂结构
作者：
T. Stallard;S. Miller;M. Lystrup;N. Achilleos;E. Bunce;C. Arridge;M. Dougherty;S. Cowley;S. Badman;D. Talboys;R. Brown;K. Baines;B. Buratti;R. Clark;C. Sotin;P. Nicholson;P. Drossart
大多数行星极光是由电离层和磁层之间流动的电流产生的，这些电流加速撞击高层大气的高能带电粒子。在土星，这些过程碰撞激发氢，导致紫外线发射，并使氢电离，导致 H3+ 红外线发射。尽管这些极光的形态受到太阳风变化的影响，但产生它们的电流来源仍然存在争议。最近的模型预测，远离主极光椭圆区的发射只有微弱。在这里，我们报告的图像显示了主椭圆形向极地和赤道方向的发射（由低发射区域分隔）。广泛的极性发射随时间变化很大，当主椭圆具有螺旋形态时就会消失；这表明，虽然极地发射可能与太阳风动态压力的轻微增加有关，但它与强磁层压缩没有直接关系。这种极光似乎是土星独有的，无法用我们目前对土星磁层的理解来解释。赤道发射弧仅存在于地球的夜间，并且由目前未知的内部磁层过程产生。
The majority of planetary aurorae are produced by electrical currents flowing between the ionosphere and the magnetosphere which accelerate energetic charged particles that hit the upper atmosphere. At Saturn, these processes collisionally excite hydrogen, causing ultraviolet emission, and ionize the hydrogen, leading to H3+ infrared emission. Although the morphology of these aurorae is affected by changes in the solar wind, the source of the currents which produce them is a matter of debate. Recent models predict only weak emission away from the main auroral oval. Here we report images that show emission both poleward and equatorward of the main oval (separated by a region of low emission). The extensive polar emission is highly variable with time, and disappears when the main oval has a spiral morphology; this suggests that although the polar emission may be associated with minor increases in the dynamic pressure from the solar wind, it is not directly linked to strong magnetospheric compressions. This aurora appears to be unique to Saturn and cannot be explained using our current understanding of Saturn’s magnetosphere. The equatorward arc of emission exists only on the nightside of the planet, and arises from internal magnetospheric processes that are currently unknown.
DOI：
10.1029/2008ja013257
发表时间：
2008-09
期刊：
Scopus
影响因子：
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作者：
E. Bunce;C. Arridge;J. Clarke;A. Coates;S. Cowley;M. Dougherty;Jean-Claude Gérard;D. Grodent;K. Hansen;J. Nichols;D. Southwood;D. Southwood;D. Talboys
通讯作者：
E. Bunce;C. Arridge;J. Clarke;A. Coates;S. Cowley;M. Dougherty;Jean-Claude Gérard;D. Grodent;K. Hansen;J. Nichols;D. Southwood;D. Southwood;D. Talboys