Insolation and Magnetospheric-Ionospheric Coupling: Three Problems

PI的建议调查三个具体的问题，有理由怀疑电离层强烈影响以前被认为是由磁层驱动的现象。在每一种情况下，紫外线照射都会改变电离层（通过增加电导率或通过增加极风外流），这反过来又会改变这种现象。每一个问题都有望在大约一年的时间内得到解决，但仍会产生有价值的结果。三个问题中的第一个是，强烈的极光是否不仅受到先前确定的当地电离层电导率的影响，而且还受到相对半球电导率的影响。如果南半球的电导率确实影响了北方半球强烈极光的形成，反之亦然，那么电离层电导率的影响对空间天气的全球影响远比以前所认为的要大得多。第二个问题是与极风相关的外流和极雨从遥远的磁层（最终是太阳风）流入之间可能存在的耦合。在每种情况下，电子的更大的迁移率导致产生与电子流相反的电场，但在相反的意义上。由于紫外线辐射驱动的极地风通量远远超过极地雨通量，因此，当极地风较大时，极地雨可能会被驱动到更高的通量。这可以通过确定紫外线照射较高时极地雨是否更强烈来相对容易地检查。第三个问题是电离层电导率是否影响漫射极光（和/或总极光粒子降水强度）。人们普遍认为漫射极光代表了等离子体片的直接倾倒，并且没有明显的理由说明它为什么会受到来自太阳辐射的电离层电导率的影响。然而，令许多空间物理学界感到惊讶的是，离散极光被阳光抑制了。在最近的文献报告中有一些异常现象，这表明，这将是非常值得调查的等离子体片的“直接倾倒”是否真的是独立的电离层的日射。

The PI's propose to investigate three specific problems for which there is reason to suspect that the ionosphere strongly influences phenomena previously thought to be driven solely by the magnetosphere. In each of these cases, UV insolation alters the ionosphere (through increasing conductivity, or through increasing polar wind outflows), which in turn may alter the phenomena. Each problem is expected to be solved in about one year with part time effort, yet yield worthwhile results.The first of the three problems is whether intense aurora are affected not only by local ionospheric conductivity, as previously determined, but also by conductivity in the opposite hemisphere. If it is true that southern hemisphere conductivity affects the formation of intense aurora in the northern hemisphere and vice versa, then the influence of ionospheric conductivity has a far more global influence on space weather than previously believed.A second problem is the possible coupling between the outflows associated with polar wind and the inflows from the distant magnetosphere (and ultimately solar wind) of the polar rain. In each case, the greater mobility of electrons leads to the creation of electric fields opposing electron flows, but in the opposite sense. Because the polar wind fluxes, driven by UV insolation, far exceed polar rain fluxes, it is likely the major direction of interaction is that when the polar wind is larger, the polar rain will be driven to higher fluxes. This can be relatively easily checked by determining whether polar rain is more intense when UV insolation is higher.The third problem is whether ionospheric conductivity affects the diffuse aurora (and/or total auroral particle precipitation intensity). It is widely assumed that the diffuse aurora represents a direct dumping of the plasma sheet, and there is no obvious reason why it should be much affected by ionospheric conductivity from insolation. However it surprised much of the space physics community to learn that discrete aurora are suppressed by sunlight. There are some anomalies in recent reports in the literature which suggest that it would be well worthwhile investigating whether the "direct dumping" of the plasma sheet really is indeed independent of the insolation of the ionosphere.