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Daily bulletin on solar and geomagnetic activity from the SIDC

Vydáno: 2022 Apr 18 1307 UTC

SIDC Forecast

Sluneční erupce

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

Geomagnetism

Quiet (A<20 and K<4)

Sluneční protony

Quiet

	10cm flux	Ap
18 Apr 2022	144	010
19 Apr 2022	150	018
20 Apr 2022	150	016

Bulletin

Solar flaring activity was moderate with 4 M class flares occurring over the period. Surprisingly, the strongest of them, an M4.4 flare peaking at 22:34UT (as well as the earlier M1.5 flare peaking at 20:02UT) was from NOAA Active Region (AR) 2992 in the west and not from the strong and complex regions in the east, NOAA AR 2993 and 2994 (which yesterday produced the X flare). NOAA AR 2993 was responsible though for the recent M1.1 flare peaking at 10:27UT while the M1.3 flare peaking at 7:48UT probably has contributions both from NOAA AR 2993 in the east and NOAA AR 2992 in the west. Both NOAA AR 2993 and 2994 are large and complex bipolar regions with flux emergence being observed in between the two regions. They remain a very likely source for strong flaring. NOAA AR 2992 seemed to develop new spots over the period, but is becoming hard to analyse more precisely as it approaches the west limb. As in the past 24h the region contributes to the potential for strong flares. Overall flares at M level are likely with also a very significant chance for X flares, from the regions in the east.

A filament eruption is associated to the flaring activity from NOAA AR 2992. SoHO LASCO images show two possibly associated signatures: a front towards the south visible from 16:36UT in LASCO C2, and one towards the south-west from 2012UT onwards. Unfortunately C2 images are lacking in between those two timestamps. It is not fully clear whether the first CME front is associated to the eruption from near NOAA AR 2992. A better assessment will be made as more information becomes available, but based on the extent and direction observed in LASCO C3 we currently judge the eruptions to be too far off the Sun-Earth line to reach Earth.

The greater than 10 MeV proton flux was at background levels and is expected to remain so. The greater than 2 MeV electron flux reached briefly above the 1000 pfu alert threshold at the diurnal maximum. The 24h electron fluence reached moderate levels and is expected to be normal to moderate, given the continuing high speed stream Solar wind conditions.

Solar wind speed increased again from around 500 km/s to hovering around 550 km/s, indicating continued high speed stream conditions. The interplanetary magnetic field was between 5-10nT with a variable north- south component, and an orientation indicating connection to a positive polarity sector. Solar wind conditions are expected to slowly subside with tomorrow morning to noon a possible increase from a potential glancing blow of the April 17 CME, though chances for this are low.

Geomagnetic conditions were quiet to unsettled (NOAA Kp 2-3 and local K Belgium 1-3). Geomagnetic conditions are expected to be quiet to unsettled. But they could reach active conditions if a glancing blow from the April 17 CME occurs.

Today's estimated international sunspot number (ISN): 100, based on 19 stations.

Solar indices for 17 Apr 2022

Wolf number Catania	///
10cm solar flux	135
AK Chambon La Forêt	014
AK Wingst	014
Estimated Ap	013
Estimated international sunspot number	080 - Based on 25 stations

Noticeable events summary

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

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