Viewing archive of Wednesday, 17 May 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 May 17 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
17 May 2023	134	006
18 May 2023	136	010
19 May 2023	138	006

Solar Active Regions and flaring

The solar flaring activity was at higher levels with one M-class flare and several C-class flares being detected in the last 24 hours. The largest flare was a M9.6 flare, peaking at 16:43 UTC on May 17, associated with ARs behind the east limb (S23E89), that are currently rotating onto the disk. The region produced the majority of the flaring activity. Low flaring activity was also produced by NOAA AR 3305 (beta class). The remaining regions on the solar disk were inactive. The solar flaring activity is expected to be at low levels, with C-class flares likely and a chance for M-class flares.

Coronal mass ejections

Several coronal mass ejections (CME) and flows were observed in the available SOHO/LASCO coronagraph imagery and automatically detected by the Cactus tool over the past 24 hours. However, no clear Earth-directed coronal mass ejections were identified. In particular, a partial-halo CME was observed in SOHO/LASCO-C2 around 17:20 UTC on May 16. Since no on-disc signature of this CME was found in the visible disc of the Sun seen from Earth, we believe that this CME was directed to the backside of the Sun.

Coronal holes

Two small equatorial coronal holes crossed the central meridian today. An associated high speed stream in in-situ solar wind measurements is expected for Apr 20.

Solar wind

The solar wind speed showed a decreasing trend over the past 24 hours, decreasing from values near 500 km/s to around 430 km/s. The interplanetary magnetic field magnitude ranged between 4 nT and 6 nT. The southward component of the interplanetary magnetic field fluctuated between -3 nT and 5 nT. The solar wind speed is expected to continue to gradually decrease over the next days.

Geomagnetism

During last 24 hours the geomagnetic conditions were at quiet levels (NOAA KP 1-2 and Local K Dourbes 1-2). Geomagnetic conditions are expected at quiet to unsettled levels during next days.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux was slightly elevated, remaining well below radiation storm levels. The proton flux is expected to remain below 10 pfu threshold over the next day, with a very small chance that a particle event occurs in association with an X-class flare or a coronal mass ejection.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux was below the 1000 pfu threshold and is expected to remain below this threshold for the next days.The 24h electron fluence was at normal level. The electron fluence is expected to be at normal levels in the next days.

Today's estimated international sunspot number (ISN): 101, based on 13 stations.

Solar indices for 16 May 2023

Wolf number Catania	138
10cm solar flux	134
AK Chambon La Forêt	///
AK Wingst	008
Estimated Ap	009
Estimated international sunspot number	100 - Based on 29 stations

Noticeable events summary

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

All times in UTC

<< Go to daily overview page