Vaata pühapäev, 25 september 2022 arhiivi

Daily bulletin on solar and geomagnetic activity from the SIDC

Välja antud: 2022 Sep 25 1247 UTC

SIDC Forecast

Päikesepursked ehk loited

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

Geomagnetism

Active conditions expected (A>=20 or K=4)

Päikese prootonid

Quiet

	10cm flux	Ap
25 Sep 2022	147	012
26 Sep 2022	145	021
27 Sep 2022	143	031

Bulletin

Solar flaring activity was low. Several C-class flares were released both by Catania group 47 (NOAA active region 3107) and by Catania group 48 (NOAA active region 3110). The strongest class reached was C7.2 and both of the regions released a flare of this class. The one from Catania group 47 (NOAA active region 3107) peaked at 16:07UTC. The one from Catania group 48 (NOAA active region 3110) peaked at 17:19UTC. Both these regions remain the main actors with the other regions on disc stable or simplifying. Catania group 48 (NOAA active region 3110) grew but seemed to consolidate and stabilize towards the end of the period. Catania group 47 (NOAA active region 3107) remains the most complex with mixed polarity field in the intermediate areas. C level flaring is expected with a very significant chance for another M flare particularly from Catania group 47 (NOAA active region 3107).

A more detailed model run for the West-bound CME of September 23 shows a possible glancing blow in the late hours of September 27. The CME associated with the M1 flare from Catania group 48 (NOAA active region 3110) occurring close to the Eastern limb on September 23 has been analyzed more closely. It is visible in SoHO/LASCO C2 images from around 18:12UTC with a projected speed of 1500km/s. Although directed well off the Sun-Earth line, given the speed of the CME a possible shock arrival can not be excluded and model runs indicate it could occur late tomorrow or in the early hours of September 27. Some more CMEs have occurred in coronagrpah images since, but all are judged to be too narrow are off the Sun-Earth line to reach Earth. On September 24 we have first a South-West bound CME at 7:12UTC which is originating from the South-West limb. In the afternoon there was an East bound CME associated to the C7.2 flare from Catania group 48 (NOAA active region 3110) followed by a rather narrow CME to the South-East from a filament eruption in the South-Eastern quadrant. None of these are expected to influence Earth.

In the past 24 hours the greater than 10 MeV proton flux remained just very slightly enhanced but well below the minor storm warning threshold. The greater than 10 MeV proton flux is expected to remain slightly enhanced, but below the radiation storm thresholds over the next 24 hours. The greater than 2 MeV electron flux was below the 1000 pfu threshold. The 24h electron fluence was at normal levels over the past 24 hours but with an increasing trend. The 24h electron fluence is expected to remain normal in the next 24 hours.

The low latitude extension of the southern polar coronal hole that transited the central meridian in the past days is expected to influence solar wind starting from around September 27.

Solar wind parameters reflected slightly perturbed solar wind conditions. Solar wind speed varied between 400-500 km/s but finally decreases to currently 360 km/s. The interplanetary magnetic field had a magnitude of between 4-6.5nT. IT is now believed that the just mildly enhanced velocities of the recent days must be associated to the coronal hole that passed central meridian on September 19, with a amuch weaker influence than anticipated. Essentially slow Solar wind conditions are expected initially with later some perturbations coming up. Through September 27 possible glancing blows from the September 23 CMEs may blend into the expected high speed stream from the extension of the southern polar coronal hole.

Geomagnetic conditions were quiet to unsettled (NOAA Kp 2-3) with locally an isolated active period (local K Dourbes 0-4). Initially quiet to unsettled conditions are expected with later, early September 27, active periods likely with the expected perturbed solar wind conditions.

Today's estimated international sunspot number (ISN): 136, based on 13 stations.

Solar indices for 24 Sep 2022

Wolf number Catania	///
10cm solar flux	147
AK Chambon La Forêt	020
AK Wingst	017
Estimated Ap	018
Estimated international sunspot number	137 - Based on 15 stations

Noticeable events summary

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

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