An interplanetary shock wave hit our planet's geomagnetic field on June 27, 2013 at approximately 14:20 UTC. Geomagnetic Sudden Impulse was registered at 14:40 UTC. The impact was relatively weak and has not caused a geomagnetic storming so far. The a deviation in ground currents was detected by magnetometer located in Kiruna, Sweden, which is clear signal of the passage of an interplanetary shock past our planet.
Active geomagnetic levels with minor storm periods are possible in the next 24 hours as a consequence of the expected arrival of a new coronal hole high speed stream. The coronal hole high speed stream's geomagnetic effects will likely decrease on June 29, 2013 when quiet to active levels are expected.
Big Earth-facing coronal hole seen in early hours of June 28, 2013 by SDO's combined AIA and STAR active regions and coronal holes map (Credit: SDO)
Solar activity has been low during the past 24 hours, featuring two low C flares from AR 1774 and 1778. A solar filament lifted off from the Sun (June 24-25, 2013) and created channel of plasma. Some plasma separated from the filament and fell down to near the solar surface.
When the plasma blobs fell down to lower atmospheric heights, the high-speed downward-traveling plasma collided with plasma at lower atmospheric heights, causing the plasma to brighten and spread out. Filaments are cooler clouds of unstable, dense plasma suspended above the Sun's surface by magnetic forces.
The event was observed in extreme ultraviolet light by SDO:
There are currently 5 numbered sunspot regions on the disk. All active regions are stabile. NOAA/SWPC forecasters estimate only 10% chance of M-class solar flare.
Prominence, active regions and coronal hole seen on SDO's AIA 304 image taken at 00:30 UTC on June 28, 2013 (Credit: SDO)
Featured image: AIA 304 (Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams)