Viewing archive of Thursday, 13 May 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 May 13 1313 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
13 May 2021	075	007
14 May 2021	074	001
15 May 2021	073	007

Bulletin

Solar activity was very low over the past 24 hours. NOAA Active Region (AR) 2822 (Catania sunspot group 93, mag. configuration Beta-delta) produced only B-class flares and continues to decay. NOAA AR 2823 is smaller, less active, and in a decaying phase. NOAA AR 2821 has a simple magnetic configuration and is not expected to produce strong flares. Solar activity is expect to decrease over the next 24 hours with a small chance of C-class events.

No Earth-directed Coronal Mass Ejections (CMEs) have been detected in the available coronagraphic 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 remained below the 1000 pfu in the past 24 hours and is expected to remain so. The 24-hour electron fluence was at nominal levels in the past 24 hours and is expected to remain so.

The geomagnetic conditions are still affected by the Interplanetary Coronal Mass Ejection (ICME) that arrive at 05:49UT 12 Mar. The solar wind speed reached a pick of 550 km/s during the last hours of the 12 Mar and has gradually decreased to 400 km/s. The total magnetic field strength (Btot) increased to 20 nT during the 12 Mar and has gradually decreased to 8 nT. The Bz component of the magnetic field had very negative values (directed toward the Sun), down to -20 nT, until approximately 14:30 UT 12 Mar. Since then it fluctuated between -10 and +10 nT, with mostly positive values. The electron density increased to approximately 80 electorns/cm3 and fluctuated a lot as a result of the ICME, but stabilized after 15:00UT 12 Mar to approximately 10 electorns/cm3. The gradual decrease of the solar wind is expected to continue for the next 24 hours. The Btot and Bz are expected to continue their gradual decrease and the Bz is expected to have positive values. The electron density is expected to remain low in the next 24 hours and not to exceed the 10 electorns/cm3.

The arrival of the ICME caused a strong geomagnetic storm (NOAA Kp index 7 between 12:00 and 18:00 UT and local K Dourbes index 6 between 14:00 and 18:00 UT). However, it quickly dropped to active levels (NOAA Kp index 4 between 18:00 and 24:00 UT) and then to quiet conditions (NOAA Kp index 2 between 00:00 and 12:00 UT). The geomagnetic activity is expected to remain in quiet levels for the next 24 hours.

Today's estimated international sunspot number (ISN): 027, based on 15 stations.

Solar indices for 12 May 2021

Wolf number Catania	033
10cm solar flux	075
AK Chambon La Forêt	050
AK Wingst	033
Estimated Ap	035
Estimated international sunspot number	031 - Based on 35 stations

Noticeable events summary

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

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