Space storm measurements of the July 2005 solar extreme events from the low corona to the Earth

Abstract

The Athens Neutron Monitor Data Processing (ANMODAP) Center recorded an unusual Forbush decrease with a sharp enhancement of cosmic ray intensity right after the main phase of the Forbush decrease on 16 July 2005, followed by a second decrease within less than 12 hours. This exceptional event is neither a ground level enhancement nor a geomagnetic effect in cosmic rays. It rather appears as the effect of a special structure of interplanetary disturbances originating from a group of coronal mass ejections (CMEs) in the 13-14 July 2005 period. The initiation of the CMEs was accompanied by type IV radio bursts and intense solar flares (SFs) on the west solar limb (AR 786); this group of energetic phenomena appears under the label of Solar Extreme Events of July 2005. We study the characteristics of these events using combined data from earth (the ARTEMIS IV radioheliograph, the Athens Neutron Monitor (ANMODAP)), space (WIND/WAVES) and data archives. We propose an interpretation of the unusual Forbush profile in terms of a magnetic structure and a succession of interplanetary shocks interacting with the magnetosphere.

Total electron content in the Mars ionosphere: Temporal studies and dependence on solar EUV flux

“…We can see that there was little dust activity in the lower Martian atmosphere at the time. There was however substantial solar activity, which persisted from June until September 2005 (Ls = −130° to −80°) [ Caroubalos et al , 2009], in localized active regions on the sun, which rotated in and out of view of the Earth‐based instruments recording solar X‐rays and solar EUV (i.e., solar rotation caused the modulations apparent in Figures 2e and 2f) and the MGS MAG/ER and Mars Express ELS instruments measuring SEP flux proxies [ Brain et al , 2010].…”

“…Though Earth and Mars were separated by a relatively small angular distance (30°–45°) during this time, the longevity of these solar disturbances (coupled with solar rotation) implies that significant ionization effects on the Martian atmosphere during this time would be likely, regardless of the separation. The disturbances modulated the EUV flux by ∼30% and caused more than a dozen large flares observed at Earth during this time, three of which reached X‐class [ Caroubalos et al , 2009]. In addition, three separate SEP events occurred at Mars between Ls = −111° and −95°, including a likely coronal mass ejection (CME) shock “spike” signature at Ls = −105° (such “spikes” in energetic particle fluxes during SEP events are signatures of accelerated plasma and in this case the spike was associated with a moderate increase in magnetic field magnitude, both common features of CME shocks [e.g., Smith and Phillips , 1997; Reames et al , 1996]), which were related to those active regions.…”