Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2026 May 29 1231 UTC

Prévisions SIDC

Éruptions solaires

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

Géomagnétisme

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

Moniteur de Flux de Proton

Quiet

	Flux de 10 cm	Ap
29 May 2026	148	014
30 May 2026	150	025
31 May 2026	151	016

Régions solaires actives et éruptions solaires

Solar flaring activity has been moderate over the last 24 hours, with one M-class flare and few C-class flares. The strongest flare was an M1.1 flare (SIDC Flare 7797), peaking at 07:04 UTC on May 29, associated with SIDC Sunspot Group 860 (NOAA Active Region 4455, magnetic type beta). There are currently twelve numbered active regions on the solar disk. The most complex one is SIDC Sunspot Group 879 (NOAA Active Region 4452, magnetic type beta-gamma). SIDC Sunspot Group 883 (NOAA Active Region 4453) and SIDC Sunspot Group 872 (NOAA Active Region 4443), both with magnetic type alpha, are currently rotating across the west limb. The solar flaring activity is expected to be low to moderate over the next 24 hours, with C-class flares very likely and a chance for M-class flares

Éjection de masse coronale

A Coronal Mass Ejection (SIDC CME 661) was observed in LASCO/C2 coronagraph imagery, starting from 23:12 UTC on May 28, lifting off from the west limb. It is most likely a backsided event and it is not expected to impact Earth. No other Earth-directed CMEs were observed in the available coronagraph imagery during the last 24 hours.

Vent solaire

Over the last 24 hours, the solar wind parameters (ACE and DSCOVR) were slightly enhanced, possibly due to the arrival of a mild high- speed stream from the southern, negative polarity coronal hole (SIDC Coronal Hole 149). The solar wind speed increased from 400 km/s to 470 km/s and then decreased to around 430 km/s. The interplanetary magnetic field was between 5 nT and 10 nT. The Bz component varied between -8 nT and 7 nT. The interplanetary magnetic field angle phi was predominantly in the negative sector. Mostly slow solar wind conditions are expected over the next 24 hours, with a chance for further enhancements due to the possible arrival of a mild high-speed stream from the northern, negative polarity coronal hole (SIDC Coronal Hole 142).

Géomagnétisme

Geomagnetic conditions globally were mostly unsettled (NOAA Kp 3- to 3), reaching active levels (NOAA Kp 4- ) between 15:00 and 18:00 UTC on May 28. Geomagnetic conditions locally were mostly unsettled (K Bel 3). Mostly unsettled to active conditions (NOAA Kp 3 to 4), with a small chance of isolated minor storm intervals (NOAA Kp 5) are expected over the next 24 hours, due to the possible arrival of a mild high-speed stream from the northern, negative polarity coronal hole (SIDC Coronal Hole 142).

Niveaux de flux de protons

The greater than 10 MeV proton flux was below the 10 pfu threshold during the last 24 hours. It is expected to remain below the threshold level over the next 24 hours.

Flux d'électrons sur l'orbite géostationnaire

The greater than 2 MeV electron flux measured by GOES 18 and GOES 19 was slightly elevated but remained below the 1000 pfu threshold during the last 24 hours. The 24-hour electron fluence was at normal levels and it is expected to remain so over the next 24 hours.

Estimation du nombre international de taches solaires (ISN) pour aujourd'hui : 141, sur la base de 19 stations.

Indices solaires pour 28 May 2026

Nombre de Wolf, observé par Catania	207
Flux solaire à 10 cm	145
AK Chambon La Forêt	023
AK Wingst	016
Ap estimé	016
Nombre international de taches solaires estimé	158 - Basé sur 33 stations

Résumé des événements marquants

Données fournies par le Solar Influences Data analysis Center© - SIDC - Traité par SpaceWeatherLive