Affichage des archives de lundi, 28 juillet 2025

Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2025 Jul 28 1237 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 Jul 2025	143	008
29 Jul 2025	141	013
30 Jul 2025	141	017

Régions solaires actives et éruptions solaires

Solar flaring activity was at low levels with low C-class flaring over the past 24 hours. A total of 11 numbered sunspot groups were identified on the visible solar disk most of them being small, simple and inactive. Most of the flaring activity, including a C3.1 flare (SIDC Flare 4958) with peak time 18:44 UTC on July 27, was produced by a returning region close to the east limb, namely SIDC Sunspot Group 555 (NOAA Active Regions 4141, 4161). SIDC Sunspot Group 570 (NOAA Active Region 4153) has also contributed to the low flaring activity over the past day, as well as SIDC Sunspot Group 572 (NOAA Active Region 4155), which has shown signatures of decay. All three active regions are classified as magnetic type beta. The solar flaring activity is expected to remain at low levels over the next 24 hours, with very likely C-class flares and a chance for M-class flares.

Éjection de masse coronale

No Earth-directed coronal mass ejections (CMEs) have been identified in the available coronagraph imagery.

Trous coronaux

A mid-latitudinal negative polarity coronal hole (SIDC 121), which first crossed the central meridian on July 26, continues to reside there. High-speed stream related to SIDC 121 is expected to reach Earth on July 29.

Vent solaire

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) have reflected nominal background slow solar wind conditions. The interplanetary magnetic field (B) was rather weak with magnitude below 3 nT and a minimum Bz of -3.6 nT. The solar wind speed was below 500 km/s. The B field phi angle was predominantly in the negative sector (directed towards the Sun). The solar wind conditions are expected to become elevated under the influence of a high speed stream starting from July 29.

Géomagnétisme

The geomagnetic conditions over the past 24 hours were globally quiet. Locally a single unsettled period was registered over Belgium between 18:00 and 19:00 UTC on July 27. Mostly quiet to unsettled geomagnetic conditions are expected for the next 24 hours. Active periods to isolated minor storms levels can be reached later on July 29 with an expected high speed stream arrival from a negative polarity coronal hole.

Niveaux de flux de protons

Over the past 24 hours the greater than 10 MeV GOES proton flux has been at nominal levels. The greater than 10 MeV GOES proton flux is expected to remain at nominal levels over the next days.

Flux d'électrons sur l'orbite géostationnaire

The greater than 10 MeV GOES 16 and GOES 18 electron fluxes were oscillating around the 1000 pfu threshold over the last 24 hours and are expected to continue to do so in the next 24 hours. The 24-hour electron fluence was at the border of nominal to moderate levels and is expected to remain so in the next 24 hours.

Estimation du nombre international de taches solaires (ISN) pour aujourd'hui : 133, sur la base de 15 stations.

Indices solaires pour 27 Jul 2025

Nombre de Wolf, observé par Catania	///
Flux solaire à 10 cm	145
AK Chambon La Forêt	008
AK Wingst	004
Ap estimé	004
Nombre international de taches solaires estimé	138 - 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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