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Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2025 Oct 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 Oct 2025	127	012
27 Oct 2025	125	043
28 Oct 2025	125	055

Régions solaires actives et éruptions solaires

Solar flaring activity was low over the past 24 hours, with several C-class flares recorded. The largest flare was a C2.2 flare (SIDC Flare 5873), peaking at 23:10 UTC on October 25, associated with SIDC Sunspot Group 653 (NOAA Active Region 4267; magnetic type alpha). There are currently seven numbered active regions on the visible solar disc. SIDC Sunspot Group 653 (NOAA Active Region 4267) was the main driver of the flaring activity observed over the past 24 hours, together with SIDC Sunspot Group 672 (NOAA Active Region 4256). The remaining active regions are relatively simple (magnetic type alpha or beta) and did not produce any significant flaring activity. Solar flaring activity is expected to be low over the next 24 hours, with C-class flares very likely and a small chance for M-class flares.

Éjection de masse coronale

Two halo coronal mass ejections (SIDC CME 587 and SIDC CME 588) were observed in SOHO/LASCO-C2 coronagraph data from 07:48 UTC and 11:24 UTC on October 25, respectively. These CMEs are directed primarily toward the southwest and northeast from Earth's perspective. Analysis indicates that the sources of these CMEs were on the far side of the Sun. Therefore, no impact on the solar wind conditions near Earth is expected. No other Earth-directed CMEs were detected in the available coronagraph imagery over the past 24 hours.

Vent solaire

Over the past 24 hours, solar wind parameters (ACE and DSCOVR) reflected the waning influence of a high-speed stream (HSS). The solar wind speed ranged between 380 km/s and 480 km/s. The interplanetary magnetic field remained weak, below 6 nT, and its southward component fluctuated between -5 nT and 6 nT. Slow solar wind conditions are expected over the next 24 hours, with a chance of a weak enhancement on October 27-28 due to possible glancing blow from SIDC CME 586 and arrival of a high-speed stream from a large positive polarity coronal hole (SIDC Coronal Hole 134).

Géomagnétisme

Geomagnetic conditions were quiet globally and quiet to unsettled locally over Belgium (NOAA Kp: 1 to 2; K-Bel: 1 to 3). Mostly quiet geomagnetic conditions are expected on October 26. On October 27-28, geomagnetic conditions are expected to reach active and minor storm levels, with a chance of isolated moderate storm periods due to possible glancing blow from SIDC CME 586 and the expected high-speed stream arrival from a large recurrent positive polarity coronal hole (SIDC Coronal Hole 134).

Niveaux de flux de protons

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

Estimation du nombre international de taches solaires (ISN) pour aujourd'hui : 102, sur la base de 12 stations.

Indices solaires pour 25 Oct 2025

Nombre de Wolf, observé par Catania	///
Flux solaire à 10 cm	127
AK Chambon La Forêt	009
AK Wingst	008
Ap estimé	010
Nombre international de taches solaires estimé	098 - Basé sur 12 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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