|Title||Influence of short-term solar disturbances on the fair weather conduction current|
|Publication Type||Journal Article|
|Year of Publication||2014|
|Authors||Elhalel G., Yair Y., Nicoll K., Price C., Reuveni Y., Harrison R.G|
|Journal||Journal of Space Weather and Space Climate|
|Type of Article||Article|
The fair weather atmospheric electrical current (J(z)) couples the ionosphere to the lower atmosphere and thus provides a route by which changes in solar activity can modify processes in the lower troposphere. This paper examines the temporal variations and spectral characteristics of continuous measurements of J(z) conducted at the Wise Observatory in Mitzpe-Ramon, Israel (30 degrees 35' N, 34 degrees 45' E), during two large CMEs, and during periods of increased solar wind density. Evidence is presented for the effects of geomagnetic storms and sub-storms on low latitude J(z) during two coronal mass ejections (CMEs), on 24-25th October 2011 and 7-8th March 2012, when the variability in J(z) increased by an order of magnitude compared to normal fair weather conditions. The dynamic spectrum of the increased J(z) fluctuations exhibit peaks in the Pc5 frequency range. Similar low frequency characteristics occur during periods of enhanced solar wind proton density. During the October 2011 event, the periods of increased fluctuations in J(z) lasted for 7 h and coincided with fluctuations of the inter-planetary magnetic field (IMF) detected by the ACE satellite. We suggest downward mapping of ionospheric electric fields as a possible mechanism for the increased fluctuations.