Affichage des archives de samedi, 25 octobre 2025

Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2025 Oct 25 1231 UTC

Prévisions SIDC

Éruptions solaires

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

Géomagnétisme

Quiet (A<20 and K<4)

Moniteur de Flux de Proton

Quiet

	Flux de 10 cm	Ap
25 Oct 2025	133	017
26 Oct 2025	135	017
27 Oct 2025	137	043

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 C1.6 flare (SIDC Flare 5872), peaking at 10:23 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). SIDC Sunspot Group 607 (NOAA Active Region 4254; magnetic type alpha) is approaching the west limb. A new region emerged and was numbered SIDC Sunspot Group 683 (magnetic type beta) near S12E51, but remained quiet. 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

The faint coronal mass ejection (SIDC CME 586) was observed in SOHO/LASCO-C2 imagery, starting at 14:36 UTC on October 23 and first reported yesterday. While the bulk of the ejecta is expected to miss Earth, a mild glancing blow could be possible on October 27. No other Earth-directed CMEs were detected in the available coronagraph imagery over the past 24 hours.

Trous coronaux

A large recurrent positive polarity coronal hole (SIDC Coronal Hole 134) reached the central meridian at around 12:00 UTC today. An associated high-speed stream may affect the solar wind environment near Earth from late October 27.

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 decreased from 580 to 430 km/s. The interplanetary magnetic field remained weak, below 6 nT, and its southward component fluctuated between -6 nT and 6 nT. A gradual transition to slow solar wind conditions is expected over the next few days, with a chance of a weak enhancement from October 27 due to the possible glancing blow from SIDC CME 586 and the arrival of a high-speed stream from a large positive polarity coronal hole (SIDC Coronal Hole 134).

Géomagnétisme

Geomagnetic conditions reached active levels globally (NOAA Kp = 4) between 03:00 and 06:00 UTC on October 25 and locally over Belgium (K-Bel = 4) at around 18:00 UTC on October 24, due to mild HSS influence. Mostly unsettled geomagnetic conditions are expected over the next 24 hours. 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 the expected HSS and a possible glancing blow from SIDC CME 586.

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 : 099, sur la base de 07 stations.

Indices solaires pour 24 Oct 2025

Nombre de Wolf, observé par Catania	105
Flux solaire à 10 cm	134
AK Chambon La Forêt	020
AK Wingst	012
Ap estimé	012
Nombre international de taches solaires estimé	098 - Basé sur 26 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

<< Aller à l'aperçu quotidien