کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1777037 | 1021721 | 2011 | 12 صفحه PDF | دانلود رایگان |
For over an entire solar cycle, from the end of 1974 until the beginning of 1986, the twin Helios spacecraft explored the inner heliosphere. These in situ, high-resolution plasma and magnetic field measurements covered heliocentric distances between 0.3 and 1 AU from the Sun and are of particular interest to studies of space weather phenomena. During this period the two spacecraft detected 395 ICME-driven shocks and these waves were found to be driven by interplanetary coronal mass ejections (ICMEs). Based on these multi-spacecraft measurements, which include a third vantage point with the observations from ISEE-3/IMP-8, the longitudinal extent of the shock waves were measured in the inner heliosphere. It was found that shock waves have about a 50% chance to be observed by two different locations separated by 90°90°. In practice, one can expect with about a 50% chance that the shock driven by a limb coronal mass ejections (CMEs) will hit the Earth, considering the expansion in longitude of shock waves driven by their associated ICMEs. For a larger separation the uncertainty increases, as only a few cases could be observed. With the absence of simultaneous solar disk observations one can then no longer unequivocally identify the shock waves observed at each spacecraft.
Research highlights
► Shock waves can extend to large longitudinal angles.
► A limb CME driven shock has about 50% chance to hit the Earth.
► A significant number of single-spacecraft observations were found for small angular distances between the observations locations.
Journal: Journal of Atmospheric and Solar-Terrestrial Physics - Volume 73, Issue 10, 20 June 2011, Pages 1281–1292