Affichage des archives de dimanche, 28 décembre 2025

Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2025 Dec 28 1259 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
28 Dec 2025	185	008
29 Dec 2025	183	010
30 Dec 2025	181	014

Régions solaires actives et éruptions solaires

Solar flaring activity was low over the past 24 hours, with only C-class flares identified. The largest flare was a C9.8 flare (SIDC Flare 6508) peaking on December 27 at 22:33 UTC, which was produced by a region in the south of SIDC Sunspot Group 735 (NOAA Active Region 4317). A total of 11 numbered sunspot groups were identified on the disk over the past 24 hours. SIDC Sunspot Group 740 (NOAA Active Region 4321) is the most complex region with its Beta-Gamma-Delta magnetic configuration, but it has produced only C-class flares in the past 24 hours. Solar flaring activity is expected to be low to moderate over the next 24 hours, with C-class flares expected and a chance for M-class flares.

Éjection de masse coronale

Further analysis of the coronal mass ejections (CME) detected in E limb at 02:24 UTC on Dec 27 in SOHO/LASCO-C2 data, with a projected speed of 350 km/s and a projected width of 90 degree, shows that it will not probably arrive to the Earth. This CME may possibly be associated with a M5.1 flare (SIDC Flare 6496, S09 E74) peaking at 01:50 UTC on Dec 27 that was produced by SIDC Sunspot Group 745 (NOAA Active Region 4325), but the source is not very clear. Possibly associated type II radio emissions were detected at 01:47 UTC on Dec 27. No other Earth- directed CMEs were detected in the available coronagraph observations during the last 24 hour.

Trous coronaux

SIDC Coronal Hole (CH) 128 (recurrent, elongated, positive polarity CH in the southern hemisphere) has crossed the central meridion on Dec 28. Another recurrent CH (SIDC CH 140) in the northern hemisphere, which has a negative polarity, has started to cross the central meridian on Dec 28. The HSSs from this CH is expected to impact the Earth from Dec 30-31.

Vent solaire

Over the past 24 hours, solar wind parameters continued to reflect the waning influence of a high-speed stream (HSSs) from the elongated, positive polarity, recurrent coronal hole (SIDC Coronal Hole 128) which started to cross the central meridian on Dec 20. The solar wind speed increases occasionally due to the irregular shape of the same coronal hole. The solar wind speed ranged from 380 km/s to 620 km/s. The interplanetary magnetic field ranged between 1 nT and 6 nT, and the North- South component (Bz) ranged between -5 nT and 5 nT. In the next 24 hours, mildly enhanced solar wind conditions are possible due to the irregular shape of the same coronal hole and then later a gradual transition to slow solar wind.

Géomagnétisme

Geomagnetic conditions were globally at quiet to unsettled conditions (NOAA Kp 1 to 3), and locally over Belgium at quiet (K BEL 1 to 2) during the past 24 hours, and it is expected to remain so for the next 24 hours.

Niveaux de flux de protons

The greater than 10 MeV GOES proton flux was below the threshold level over the past 24 hours and it is expected to remain so for the next 24 hours.

Flux d'électrons sur l'orbite géostationnaire

The greater than 2 MeV electron flux, as measured by GOES-18 and GOES-19 satellites, was above the 1000 pfu threshold for most of the time during the past 24 hours. It was in response to the high speed streams (HSS) from the southern, positive polarity, recurrent coronal hole (SIDC Coronal Hole 128) which started to cross the central meridian from Dec 20. The electron flux is expected to remain above this alert level during most of the next period. The electron fluence was at moderate levels and is expected to remain so.

Estimation du nombre international de taches solaires (ISN) pour aujourd'hui : 139, sur la base de 09 stations.

Indices solaires pour 27 Dec 2025

Nombre de Wolf, observé par Catania	///
Flux solaire à 10 cm	178
AK Chambon La Forêt	011
AK Wingst	006
Ap estimé	006
Nombre international de taches solaires estimé	140 - Basé sur 18 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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