Viewing archive of Wednesday, 31 March 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Mar 31 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
31 Mar 2021	074	007
01 Apr 2021	074	004
02 Apr 2021	074	009

Bulletin

Solar activity was at low levels over the past 24 hours with no sunspot on the visible solar disc. The Catania sunspot group 83 (NOAA-AR 2812) has fully decayed and turned into a plage. The Catania sunspot group 82 (NOAA-AR 2811) that turned into a plage yesterday on Mars 30 produced a B7.4-class flare peaking on Mars 30, at 20:18 UTC (when the plage was located at 48 degree longitude and 20 degree latitude). The B-class flare was associated with the coronal mass ejection ejected with a speed of about 400 km/s and observed in LASCO images on Mars 31 around 05:15 UTC. Solar activity is expected to remain at low levels.

No Earth-directed coronal mass ejections (CMEs) was observed in the available coronagraph imagery.

The greater than 10 MeV proton flux was at nominal levels over the past 24 hours and is expected to remain so for the next 24 hours. The greater than 2 MeV electron flux was below the 1000 pfu threshold in the past 24 hours and is expected to remain so during the next 24 hours. The 24h electron fluence is at normal levels in the last 24 hours and is expected to stay at normal levels for the next 24 hours.

The solar wind parameters (ACE and DSCOVR) were mostly close to nominal levels over the past 24 hours with mild enhancements: The solar wind speed ranged between 305 km/s and 410 km/s . The interplanetary magnetic field magnitude reached about 8.6 nT, and Bz components varied between -6.8 nT and 4.2 nT. The slight enhancement was due to the high-speed stream effects associated with the small patchy equatorial coronal holes (in the south hemisphere, with negative polarity). The Earth is expected to remain in mostly slow solar wind regime for the next 24-hour period. A large equatorial coronal hole (with a positive magnetic polarity) is currently facing Earth. The high-speed stream associated with this coronal hole is expected to reach Earth in about 2-3 days.

Geomagnetic conditions were mostly quiet (Kp and K-Dourbes: 0-2) with some unsettled periods (Kp and K-Dourbes: 3). Quiet conditions are expected with possible short periods of unsettled conditions due to the slight enhancement of the solar wind especially if the interplanetary magnetic field Bz component remain negative for a longer period of time.

Today's estimated international sunspot number (ISN): 000, based on 21 stations.

Solar indices for 30 Mar 2021

Wolf number Catania	012
10cm solar flux	080
AK Chambon La Forêt	011
AK Wingst	005
Estimated Ap	004
Estimated international sunspot number	012 - Based on 28 stations

Noticeable events summary

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

All times in UTC

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