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Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2025 Dec 05 1233 UTC

Prévisions SIDC

Éruptions solaires

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

Géomagnétisme

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

Moniteur de Flux de Proton

Warning condition (activity levels expected to increase, but no numeric forecast given)

	Flux de 10 cm	Ap
05 Dec 2025	222	008
06 Dec 2025	220	020
07 Dec 2025	220	016

Régions solaires actives et éruptions solaires

Solar flaring activity over the past 24 hours was low with only C-class flares identified. The strongest activity was a C7.3 flare (SIDC Flare 6291) with peak time 02:09 UTC on Dec 05, produced by SIDC Sunspot Group 687 (NOAA Active Regions 4274, 4299). The region exhibits beta-delta magnetic configuration and has decreased in size. A total of 8 sunspot groups were identified on the visible solar disk. SIDC Sunspot Group 709 (NOAA Active Region 4294) and SIDC Sunspot Group 712 (NOAA Active Region 4296) remain the largest and most complex regions, both classified as magnetic type beta-gamma-delta. SIDC Sunspot Group 711 (NOAA Active Region 4297) has decayed, while SIDC Sunspot Group 715 (NOAA Active Region 4301) has exhibited some growth. The solar flaring activity is expected to be at moderate levels over the next 24 hours with background C-class flaring, likely M-class flares and chances of isolated X-class flaring.

Éjection de masse coronale

The coronal mass ejection (CME) detected in the LASCO/C2 imagery starting at 06:36 UTC on Dec 04 following the C4.4 flaring with peak time 05:38 UTC produced by SIDC Sunspot Group 709 (NOAA Active Region 4294) and related to a coronal dimming first observed at 05:33 UTC was accompanied by a type IV radio burst registered at 08:32 UTC. The bulk of the CME is expected to miss the Earth with chances for a minor glancing blow mixed within the ambient fast solar wind late on Dec 06 or Dec 07. No other Earth-directed CMEs have been identified in the available coronagraph imagery over the past 24 hours.

Vent solaire

Over the past 24 hours the solar wind parameters (as measured by ACE at L1) continued to register the influence of a high-speed stream related to the re-current negative polarity coronal hole (SIDC 140). The solar wind speed was consistently above 600 km/s, reaching values up to 771 km/s. The magnitude of the interplanetary magnetic field, B, was mildly elevated with values up to 8.8 nT and a Bz component registering a minimum of -8.2 nT. The B field phi angle was predominantly in the negative sector (directed towards the Sun) reflecting the polarity of the geo-effective coronal hole. The solar wind conditions are expected to remain elevated over the next days under the ongoing influence of the high-speed stream with chances for additional minor enhancements on Dec 06 and Dec 07 related to any possible glancing blow influence from the modelled CMEs, which launched from the Sun on Dec 03 and Dec 04.

Géomagnétisme

The geomagnetic conditions over the past 24 hours were predominantly unsettled to active. Unsettled at active conditions are expected to prevail over the next days with remaining chances for isolated minor storm levels due to an ongoing influence of a high speed stream.

Niveaux de flux de protons

Over the past 24 hours the greater than 10 MeV GOES proton flux has been at nominal levels and is expected to remain so over the next days with chances for some enhancements related to possible high flaring activity.

Flux d'électrons sur l'orbite géostationnaire

The greater than 2 MeV electron flux (as measured by GOES 18 and GOES 19) was below the 1000 pfu threshold over the last 24 hours. It might exceed the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence was at nominal levels and is expected to remain at nominal levels over the next 24 hours.

Estimation du nombre international de taches solaires (ISN) pour aujourd'hui : 177, sur la base de 05 stations.

Indices solaires pour 04 Dec 2025

Nombre de Wolf, observé par Catania	///
Flux solaire à 10 cm	220
AK Chambon La Forêt	031
AK Wingst	028
Ap estimé	030
Nombre international de taches solaires estimé	184 - Basé sur 11 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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