Viewing archive of Monday, 11 September 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Sep 11 1240 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
11 Sep 2023	164	007
12 Sep 2023	164	007
13 Sep 2023	164	007

Solar Active Regions and flaring

The solar flaring activity was at moderate levels with two M1-class flares and one C9-class flare. The first M1.4-class flare occurred in the NOAA Active Region 3429 peaking at 01:28 UTC on September 11. In associated to the flare, a Type II emissions occurred usually indicating that a coronal mass ejection is associated with this flare event. NOAA Active Region 3431 produced the second M1.1-class flare peaking at 04:28 UTC on September 11, and the C9.3-class flare peaking at 06:01 UTC. NOAA AR 3423 became the most complex region on the disc and is showing a beta-gamma magnetic configuration. However it did not show any significant flaring activity. All the other regions are bipolar with a beta magnetic configuration. The GOES/X-ray flux global level is currently around at C0.5 levels. The flaring activity is expected to remain at moderate with C-class flare, isolated M-class flares and possible X-class flare although less likely.

Coronal mass ejections

No clear Earth-directed Coronal Mass Ejections (CME) were observed in the SOHO/LASCO coronograph images over the past 24 hours. However, a North-West partial halo CME was observed on September 10 at 17:12 UTC with an angular width of about 105 degrees and slow speed of about 225 km/s. The source of this CME is unclear. A possible candidate is a prominence near the NOAA Active Region 3424 locate on the central meridian. In that case, a glancing blow may reach Earth not earlier than 4-5 days due to the very slow speed. Another Est partial halo CME was observed on September 11 at 01:25 UTC with an angular width of about 150 degrees and a speed of about 500 km/s. This CME is associated with the M1.4-class flare and the type II radio emission that occurred in the Catania NOAA Active Region 3429. A glancing blow may be visible in the solar wind condition near Earth in about 3.5 days.

Coronal holes

Two relatively small coronal holes have crossed the central meridian and are currently on the West hemisphere, one is located in the Northern (positive magnetic polarity) and the other one is in Southern solar hemisphere (negative magnetic polarity). The solar wind associated with these two coronal holes are expected to reach Earth starting in the afternoon of September 13. A third equatorial polar coronal hole (negative magnetic polarity) has reached the central meridian today. The high-speed streams associated to this equatorial coronal hole is expected to reach Earth in 3-4 days.

Solar wind

The solar wind parameters showed a slow solar wind regime over the past 24 hours: The wind speed was around 300 km/s in the beginning of the period and gently rise up to the current values of 400 km/h. The total interplanetary magnetic field (Bt) slowly rose to 8 nT. The southward component (Bz) was fluctuating between -6.0 nT and 6.9 nT being manly positive. The interplanetary magnetic field phi angle predominantly positive, directed outward the Sun. The solar wind parameters are expected to remain in the slow solar wind regime for the next 24 hours.

Geomagnetism

Geomagnetic conditions were at quiet (NOAA Kp < 3 and K_BEL < 3). Geomagnetic activity is expected to be mostly quiet for the next 24 hours.

Proton flux levels

The greater than 10 MeV proton flux was at background levels over the past 24 hours and is expected to remain so for the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux was below the 1000 pfu threshold. It is expected to remain below the threshold for the next 24 hours. The 24-hour electron fluence was at normal levels for the past 24 hours and it is expected to remain at these levels for the next 24 hours.

Today's estimated international sunspot number (ISN): 210, based on 20 stations.

Solar indices for 10 Sep 2023

Wolf number Catania	///
10cm solar flux	164
AK Chambon La Forêt	006
AK Wingst	003
Estimated Ap	002
Estimated international sunspot number	194 - 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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