Viewing archive of Friday, 29 September 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Sep 29 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
29 Sep 2023	144	010
30 Sep 2023	140	012
01 Oct 2023	136	012

Solar Active Regions and flaring

Solar flaring activity over the past 24 hours was at low levels. The largest flare was a C3-flare, with peak time 14:04 UTC on September 28 and was associated with NOAA AR 3450, which has continued to emerge. There are currently 7 numbered active regions on the visible disk. NOAA AR 3435 (beta) has started to rotate over the west limb, NOAA AR 3445 (beta) has decayed but produced the most C-class flares and NOAA AR 3449 (beta-gamma) has remained stable, all other regions have simple alpha or beta magnetic field configurations. The solar flaring activity is likely to be at low levels over the coming days with C-class flares expected, M-class flares possible and a low chance for isolated X-class flaring.

Coronal mass ejections

No Earth directed CMEs have been detected in the last 24 hours.

Coronal holes

A positive polarity coronal hole is passing the central meridian in the northern hemisphere.

Solar wind

In the last 24 hours, the interplanetary magnetic field fluctuated between 5 nT and 8 nT. The Bz fluctuated between positive and negative values until around 23:00 UTC on September 28, after which there was an extended period of negative Bz with a minimum value of – 8 nT. The solar wind speed had values varying between around 400 km/s and around 500 km/s. The phi-angle was mainly in the positive sector (directed away from the Sun) with a period in the negative sector (directed towards the Sun) between 04:35 UTC and 08:46 UTC on September 29. Slow solar wind conditions are expected in the next 24 hours with a possible high speed stream influence from late on September 30, associated with the positive polarity coronal hole that began to cross the central meridian on September 27.

Geomagnetism

The geomagnetic conditions over the past 24 hours were active globally (Kp 4) and locally (K Bel 4). Quiet to unsettled conditions are expected in the next 24 hours with active conditions possible from the October 1.

Proton flux levels

The greater than 10 MeV proton flux was at background level over the last 24 hours and is expected to remain so in the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES-16 was fluctuating around the 1000 pfu threshold value between 14:00 UTC and 17:30 UTC on September 29. The greater than 2 MeV electron flux is expected to increase above the threshold again in the next 24 hours. The 24h electron fluence was at moderate levels and is expected to remain at moderate levels in the next 24 hours.

Today's estimated international sunspot number (ISN): 109, based on 13 stations.

Solar indices for 28 Sep 2023

Wolf number Catania	135
10cm solar flux	148
AK Chambon La Forêt	011
AK Wingst	006
Estimated Ap	005
Estimated international sunspot number	124 - Based on 25 stations

Noticeable events summary

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

All times in UTC

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