Viewing archive of Tuesday, 11 April 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Apr 11 1231 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
11 Apr 2023	142	005
12 Apr 2023	142	005
13 Apr 2023	142	007

Bulletin

Solar flaring activity has been at low levels over the past 24 hours, with 25 C-class flares and 1 M-class flare reported. The majority of the flares originated from the Catania sunspot group 50 (NOAA AR 3272) and from NOAA AR 3276 which rotated onto the visible solar disk recently. From Catania sunspot group 50 (NOAA AR 3272), which still has a beta-gamma configuration of its photospheric magnetic field, the strongest flares originated, a GOES M1.3 flare with peak time at 10:16 UT on April 11. For the next 24 hours, we expect C-class flares and possibly also isolated M-class flares.

During the last 24 hours there were no potentially Earth-directed coronal mass ejections detected in the available coronagraph observations.

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

Over the past 24 hours, the solar wind conditions transitioned from the arrival of the ICME to fast solar wind conditions, with the arrival of the high speed stream (HSS) as a result of a small coronal hole that crossed the central meridian on April 8. Solar wind speed values between 520 and 430 km/s have been reported with a gradual decline since about 22:00 UT on April 10. During the last 24 hours, the interplanetary magnetic field strength was about 6-8 nT and the Bz-component of the magnetic field was mostly north-ward oriented. Over the next 24 hours we expect the influence of the HSS to fade. From late April 13 onwards, we are expecting the arrival of another high speed stream, associated with the positive polarity coronal hole which is crossing the central meridian today.

During the last 24 hours, the geomagnetic conditions calmed down from unsettled conditions due to the ICME arrival (K and Kp values around 3) to quiet conditions (K and Kp values around 1), with K and Kp values reported by the local station at Dourbes and NOAA, respectively. Geomagnetic conditions are expected to be quiet over the next 24 hours.

Today's estimated international sunspot number (ISN): 105, based on 20 stations.

Solar indices for 10 Apr 2023

Wolf number Catania	///
10cm solar flux	140
AK Chambon La Forêt	014
AK Wingst	///
Estimated Ap	015
Estimated international sunspot number	089 - Based on 19 stations

Noticeable events summary

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

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