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Daily bulletin on solar and geomagnetic activity from the SIDC

Випущено: 2021 Sep 06 1231 UTC

SIDC Forecast

Сонячні спалахи

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

Quiet (A<20 and K<4)

Сонячні протони

Quiet

	10cm flux	Ap
06 Sep 2021	092	006
07 Sep 2021	092	006
08 Sep 2021	088	004

Bulletin

Solar activity was at very low levels over the past 24 hours. There are currently four numbered active regions (ARs) on the visible disc, namely NOAA 2863 (beta), NOAA 2864 (beta), NOAA 2866 (beta) and the newly numbered AR NOAA 2868 (beta). All of them have showed low level of activity bellow C-class flaring. NOAA 2867 (Catania sunspot group 36) is approaching the western limb and has turned into plage. NOAA 2865 has flared off and also decayed into plage. The X-ray flare activity is expected to remain at very low to low levels for the next 24 hours with 45% probability for a C-class flare.

A filament eruption near NOAA 2865 in the afternoon of Sept 5th, followed by a B7.9-class flare (peak 18:11 UTC) and a B.7-class flare from NOAA 2866 (peak 18:56 UTC) produced an on-disc wave and a broad dimming. A resulting slow CME was ejected from the west-south region of the solar disc, with a small chance for an Earth-directed component. Further analysis of this event will be performed as more coronagraph data becomes available. Currently, due to the parameters of the CME, only minor impact could be expected, should this CME reach the Earth.

The greater than 10 MeV proton flux was at nominal levels in the past 24 hours and is expected to remain so in the next 24 hours. The greater than 2MeV electron flux was predominantly below the 1000 pfu threshold with a single short crossing in around 2pm UTC on Sept 05th. The 2MeV electron flux is expected to remain below the 1000 pfu threshold with a possibility for a short isolated crossing. The 24h electron fluence was at moderate levels and is expected to return to nominal levels in the next 24 hours.

Over the past 24 hours all solar wind parameters (ACE and DSCOVR) were at low levels. The solar wind speed was in the range of 293 to 330 km/s. The total magnetic field varied between 0.45 and 6.9 nT with a weakly varying Bz component in the range of -5.5 to +5.6 nT. The interplanetary magnetic field was predominantly in the positive sector (directed away from the Sun).

The geomagnetic conditions over the past 24 hours were mostly quiet with several isolated unsettled periods. Mostly quiet geomagnetic conditions are expected for the next 24 hours with a slight possibility for isolated intervals with unsettled conditions, should any fast solar wind stream from the coronal hole, which crossed the central meridian on Sep 2nd, arrive to the Earth.

Today's estimated international sunspot number (ISN): 086, based on 19 stations.

Solar indices for 05 Sep 2021

Wolf number Catania	///
10cm solar flux	094
AK Chambon La Forêt	011
AK Wingst	006
Estimated Ap	007
Estimated international sunspot number	075 - Based on 26 stations

Noticeable events summary

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

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