Viewing archive of Friday, 22 September 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Sep 22 1234 UTC

SIDC Forecast

Solar flares

M-class flares expected (probability >=50%)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
22 Sep 2023	168	007
23 Sep 2023	166	019
24 Sep 2023	166	013

Solar Active Regions and flaring

There are eleven active regions visible on the disk. There were two M-class flares in the last 24 hours, the strongest flare of the last 24 hours was an M8.7 from NOAA AR 3435 (beta- delta magnetic field configuration), peaking at 12:54 UTC on 21 September. NOAA ARs 3441 and 3442 have evolved into a beta-gamma magnetic field configuration. All the other regions have simpler alpha or beta magnetic field configuration. More M-class flares can be expected in the next 24 hours, X-class flares are possible.

Coronal mass ejections

A partial halo CME with angular width around 150 degrees was first seen by LASCO-C2 at 13:36 UTC on 21 September. The CME was related to the M8.7 flare from NOAA AR 3435. The CME speed was estimated to be around 500 km/s, with the bulk of the material directed to the south. Since the source is located close to disk center, an impact at Earth can be expected on 25 September.

A second wide CME was observed right after the first one, directed towards the NE, this CME is backsided and will not affect the Earth.

Coronal holes

Two small negative coronal holes crossed the central meridian on 20 September, a related (mild) high speed stream could arrive to the Earth in about 24 hours.

Solar wind

In the last 24 hours, the solar wind speed at the Earth has been around 400 km/s and the interplanetary magnetic field has decreased to 4 nT. Similar slow solar wind conditions can be expected for the next 24 hours. Nevertheless, two CMEs can arrive to the Earth and change the solar wind conditions. The first one was expected for today (with low chances of arrival) and the second one for 23 September (with higher chances of arrival). Furthermore, in about 24 hours we may observe the arrival of a (mild) high speed stream from the two coronal holes that traversed central meridian two days ago.

Geomagnetism

During the last 24 hours the geomagnetic conditions have been quiet to unsettled, both globally and locally (NOAA KP 3, K_Bel 3). Similar conditions can be expected in the next 24 hours, with possible active to minor storm levels if the CMEs and high speed stream arrive.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux was at nominal levels and is expected to remain so over the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux was below the 1000 pfu, as measured by GOES 16. It may increase over the threshold in the next 24 hours. The 24 hour electron fluence was at moderate levels, it is expected to stay at those levels for the next 24 hours.

Today's estimated international sunspot number (ISN): 222, based on 13 stations.

Solar indices for 21 Sep 2023

Wolf number Catania	///
10cm solar flux	168
AK Chambon La Forêt	015
AK Wingst	012
Estimated Ap	010
Estimated international sunspot number	200 - Based on 13 stations

Noticeable events summary

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

All times in UTC

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