Space weather highlights of the week 2015-06-18 to 2015-06-25
By Alex Wold, CCMC summer intern 2015At 2015-06-18T01:25Z, an O-type CME erupted out of AR 2365 on the west limb of the solar disk following a bright M1.2 class flare. When looking at SDO AIA 193, 171, 211, 131, and 304, the filament eruption is visible, as well as rising loops and post eruption arcades. This CME is fast moving at about 1720 km/s. Due to the good magnetic connectivity that this source location has to earth, this flare and CME resulted in a major SEP event with an increase in the GOES 10 MeV protons exceeding the 10 pfu threshold at 2015-06-18T09:25Z and the SOHO COSTEP 15.8-39.8 MeV protons exceeding the 10^(-1) pfu threshold at 2015-06-18T15:30.
At 2015-06-18T17:24Z, an O-type CME erupted at N12E44 (AR 12371) in association with an M3.0 class flare. This is especially visible in SDO AIA 171 and 193 where signatures including opening and rising field lines starting around 16:30Z, followed by dimming surrounding the AR, a two-ribbon flare, and outflows are seen. The CME was fast and bright, displaying a full halo, moving at about 1000 km/s in SOHO LASCO C2 and C3. This CME reached Earth at 2015-06-21T15:40Z causing spikes in the solar wind velocity, ACE Magnetic Field strength, ACE Density and ACE Ion Temperature.
At 2015-06-19T06:42Z, a C-type CME was detected. The source of this CME was a big filament eruption below the coronal hole south of AR 2371 at S30W10, visible in SDO AIA 211, 193, and 171 along with post eruption arcades and dimming in the area. The eruption seems to be pushed to low latitudes due to the high-speed solar wind coming from the coronal hole. This CME reached Earth at 2015-06-22T04:51Z when it caused spikes in the solar wind velocity, ACE Magnetic Field strength, ACE Density and ACE Ion Temperature.
At 2015-06-21T02:48, an O-type CME was observed erupting from N13E12 (AR 2371). This eruption was preceded by two M-class flares in the same AR, one at 2015-06-21T01:02Z and the other at 2015-06-21T02:06Z. The flares and the eruption are clearly visible in the center of the solar disk in SDO AIA 171, 193, and 131, where dimming, an EUV wave, and post eruption arcades can be identified. Due to good magnetic connectivity to earth from the source location, the flares and CME resulted in a significant SEP event starting at 2015-06-21T20:35Z. The CME reached earth at 2015-06-22T17:59Z, when it caused spikes in the solar wind velocity, ACE Magnetic Field strength, ACE Density and ACE Ion Temperature, and proceeded to cause a huge geomagnetic storm. At 2015-06-22T18:00, the NOAA Kp index reached 8. The storm continued for the next 21 hours, fluctuating between Kp levels from 6 to 8. Due to this storm, there was an increased chance of seeing the aurora at lower latitudes. The aurora was easily seen with the naked eye as far south as Northern Pennsylvania. The arrival of the CME also caused intense magnetopause crossing at 2015-06-22T18:49Z, which can have a large effect on any satellites in geosynchronous orbit. Finally, at 2015-06-24T13:10Z, the electron flux increased causing an enhancement of the radiation belt.
Two other flares from the AR 2367 contributed to the 2015-06-21T20:35Z SEP, an M3.8 and M1.1 class flare peaking at 2015-06-21T09:44Z and 2015-06-21T18:20Z, respectively.
At 2015-06-22T18:36Z, an O-type CME erupted out of AR 2371 associated with a bright M6.5 class flare from the same location, visible in SDO AIA 193, 171, 211, 304, and 131. The SOHO coronagraphs indicated that the CME was likely earth directed due to the asymmetrical halo the images displayed. The CME moved fairly quickly at about 1155 km/s and reached earth at 2015-06-24T12:57Z. The arrival of the CME resulted in a short geomagnetic storm lasting from 2015-06-25T03:00Z to 2015-06-25T06:00Z, at which time the Kp reached 6.
At 2015-06-25T08:36Z there was an O-type CME associated with an M7.9 class flare from AR 2371. The eruption is visible in SDO AIA 193, 171, 211, 304, and 131 at about N20W40 just after 08:00. There are definite post eruption arcades, and the eruption causes a EUV wave in the entire NW quadrant of the disk. This wave caused by the eruption indicates that the CME may be being pushed more eastward. In SOHO LASCO C2 and C3, there is a partial halo indicating that this CME will likely hit Earth. While the single simulation predicted a glancing blow, the ensemble simulation predicted an arrival at Earth with 58% probability. Due to strong magnetic connectivity between the source location and Earth, an SEP event began at 2015-06-26T01:20Z when the GOES13: SEM/EPS >10 MeV crossed the threshold of 10 pfu and the SOHO: COSTEP 15.8-39.8 MeV exceeded the 10^(-1) pfu threshold.
