Affichage des archives de vendredi, 26 septembre 2025

Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2025 Sep 26 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
26 Sep 2025	166	006
27 Sep 2025	164	014
28 Sep 2025	163	020

Régions solaires actives et éruptions solaires

Solar flaring activity was moderate over the past 24 hours, with only C-class flares. The strongest flare was a C3.4 flare (SIDC Flare 5562) peaking at 14:01 UTC on September 25, which was associated with SIDC Sunspot Group 640 (NOAA Active Region 4217, magnetic type beta). There are currently nine numbered active regions on the solar disk. SIDC Sunspot Groups 592, 640, 648, 644, 650 (NOAA Active Regions 4226, 4217, 4230, 4224, 4229) are the most complex, all with magnetic type beta. SIDC Sunspot Group 642 (NOAA Active Region 4221) and SIDC Sunspot Group 647 have rotated over the west limb. The solar flaring activity is expected to be low over the next 24 hours, with C-class flares very likely and a chance for M-class flares.

Éjection de masse coronale

No Earth-directed Coronal Mass Ejections (CMEs) were observed in the available coronagraph imagery in the last 24 hours.

Vent solaire

The solar wind conditions (ACE) are gradually returning to the slow solar wind regime, under the waning influence of the high-speed stream from the mid-latitude, negative polarity coronal hole (SIDC Coronal Hole 126). The solar wind speed decreased from approximately 500 km/s to approximately 430 km/s. The interplanetary magnetic field values were mostly around 5 nT. The Bz component varied between -4 nT and 5 nT. The interplanetary magnetic field angle was in the negative sector. Enhanced solar wind conditions are possible over the next 24 hours due to the high- speed stream associated with the small, equatorial, negative polarity coronal hole (SIDC Coronal Hole 132) that crossed the central meridian on September 24.

Géomagnétisme

Geomagnetic conditions globally and locally were mostly at quiet to unsettled levels (NOAA Kp 1 to 3, K BEL 1 to 3). Unsettled to active conditions are possible over the next 24 hours due to the high-speed stream associated with the small, equatorial, negative polarity coronal hole (SIDC Coronal Hole 132) that crossed the central meridian on September 24.

Niveaux de flux de protons

The greater than 10 MeV proton flux was below the 10 pfu threshold level over the past 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 below the 1000 pfu threshold in the last 24 hours. The greater than 2 MeV electron flux is expected to be below the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence is presently at normal levels and is expected to remain so over the next 24 hours.

Estimation du nombre international de taches solaires (ISN) pour aujourd'hui : 154, sur la base de 10 stations.

Indices solaires pour 25 Sep 2025

Nombre de Wolf, observé par Catania	186
Flux solaire à 10 cm	170
AK Chambon La Forêt	018
AK Wingst	007
Ap estimé	007
Nombre international de taches solaires estimé	155 - Basé sur 13 stations

Résumé des événements marquants

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

Toutes les heures sont indiquées en UTC

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