Abstract Details
| Name: Nandita Srivastava Affiliation: Udaipur Solar Observatory, PRL Conference ID: ASI2018_1428 Title : Stealth CMEs and problem geomagnetic storms Authors and Co-Authors : NA Abstract Type : Poster Abstract Category : Sun and the Solar System Abstract : Recent solar observations have shown that some solar eruptions do not display the usual low coronal signatures of CMEs, like solar flares, flows, jets, coronal dimmings or brightenings or filament eruptions. Some of these also lead to what we know as problem geomagnetic storms. During solar cycle 23, with the continuous coverage and improved sensitivity of SOHO/LASCO coronagraphs, many major geomagnetic storms were identified with full or partial halo CMEs close to the Sun. However, for a few CMEs, it was not possible to find the associated low coronal signatures or clear white-light CMEs. Also during the minimum between cycles 23 and 24, STEREO spacecraft observed Earth-directed CMEs, including CMEs with narrow angular widths, which were reported to lack solar signatures and were termed as "Stealth CMEs". The Atmospheric Imaging Assembly (AIA) on SDO which was launched in 2010 is now providing high resolution EUV images of the corona and is capable of revealing weak coronal signatures of CMEs. This improved capability combined with the twin spacecraft STEREO observations from two different vantage points can give a better understanding of Stealth CMEs and their propagation. We examine the solar and interplanetary sources of problem geomagnetic storms in an attempt to understand if the mechanisms during such eruptions are distinctly different from those associated with typical CMEs. This is crucial as eruptions with no coronal signatures can lead to unexpected strong space weather impact, since early warning signs are not present in these events. |