Viewing archive of Tuesday, 8 September 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Sep 08 1243 UTC

SIDC Forecast

Solar flares

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Quiet

	10cm flux	Ap
08 Sep 2015	084	032
09 Sep 2015	083	008
10 Sep 2015	080	010

Bulletin

Only four sunspot groups are currently visible on the solar disc, and the most complex one is NOAA AR 12412 with beta configuration of its photospheric magnetic field. Only low B-class flares were reported during last 24 hours, and we expect this low solar activity to persist with possibility of only an isolated C-class flare in the coming hours. No Earth directed CMEs were observed in the last 24 hours.

Newly available data suggest that the geomagnetic storm which started yesterday afternoon and continued until early this morning, was associated with the arrival of ICME. The partial halo CME first seen at 19:24 UT on September 4 (associated with the filament eruption from the south-east quadrant of the Sun) arrived at the Earth at about 12 UT on September 07. The ACE data showed simultaneous increase of the solar wind speed from 500 km/s up to about 600 km/s, and the increase of the interplanetary magnetic field magnitude to value of about 22 nT. The Bz component of the interplanetary magnetic field had long southward intervals (down to -12nT). This rather strong southward field and the fast solar wind produced long lasting geomagnetic storm, NOAA reported Kp=6 and local stations Dourbes and Izmiran reported K=5. Currently solar wind speed is about 500 km/s and the interplanetary magnetic field magnitude is about 22 nT. During last 8 hours the Bz component of the interplanetary magnetic field was positive, however if the Bz turns negative, and with the currently rather high value of the solar wind speed, we can expect active to storm conditions in the coming hours.

Today's estimated international sunspot number (ISN): 040, based on 13 stations.

Solar indices for 07 Sep 2015

Wolf number Catania	///
10cm solar flux	084
AK Chambon La Forêt	064
AK Wingst	036
Estimated Ap	039
Estimated international sunspot number	041 - Based on 29 stations

Noticeable events summary

Provided by the Solar Influences Data analysis Center© - SIDC - Processed by SpaceWeatherLive

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