Viewing archive of Sunday, 1 August 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Aug 01 1240 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
01 Aug 2021	076	002
02 Aug 2021	077	004
03 Aug 2021	078	004

Bulletin

The visible solar disc is spotless and the X-ray flux is below C-level. A long duration B2.4-class flare was observed near NOAA AR-2849 Plage. The solar activity is expected to remain at low levels over the next 24 hours.

A large coronal dimming associated with the long duration B2.4-class flare was observed on July 31 from 15:54 UTC to 18:06 UTC in the south-west quadrant (near latitude -12 degrees and longitude 30 degree). Further investigation on this event will be provided as data comes in.

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 was 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 (as observed by ACE and DSCOVR) show the continuation of a slow return towards an ambient background and slow solar wind speed regime. Solar wind speed decreased from about 460 km/s to 400 km/s. Total interplanetary magnetic field strength remained below 5 nT. The Bz component underwent only weak deviations between -4.0nT and +3.5 nT. The solar wind conditions are expected to continue it slow returned toward a slow solar wind speed regime. The solar wind may be temporarily slightly enhanced later today due to some possible effect of the arrival of the coronal mass ejection observed on July 28 at 10:36 UTC (with a projected speed of 400 km/s).

The geomagnetic conditions were mostly quiet over the past 24 hours with some short periods of unsettled condition observed at the local station Dourbes (K-Dourbes = 3). The conditions are expected to remain quiet as the Earth is expected to remain in the mostly slow solar wind speed regime for the next 24 hours.

Today's estimated international sunspot number (ISN): 010, based on 14 stations.

Solar indices for 31 Jul 2021

Wolf number Catania	///
10cm solar flux	076
AK Chambon La Forêt	010
AK Wingst	008
Estimated Ap	007
Estimated international sunspot number	002 - 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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