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Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2025 Aug 17 1241 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
17 Aug 2025	120	007
18 Aug 2025	120	016
19 Aug 2025	120	027

Régions solaires actives et éruptions solaires

Solar flaring activity was low over the past 24 hours, with only C-class flares identified. A total of 6 numbered sunspot groups were observed on the solar disk. Several of the SIDC Sunspot Groups have Alpha magnetic configurations and did not produce any significant flaring activity. The most productive region was SIDC Sunspot Group 590 (NOAA Active Region 4172), currently located at N09W78, which has a Beta magnetic configuration and was decreasing over the past 24 hours. This region produced the largest flare, a C3.2 flare (SIDC Flare 5165), peaking on August 16 at 21:00 UTC. Solar flaring activity is expected to remain low over the next 24 hours, with C-class flares very likely.

Éjection de masse coronale

Coronal mass ejections: No Earth-directed coronal mass ejections (CMEs) were observed over the past 24 hours. Only a very small number of minor CMEs were detected, none of which are expected to impact Earth.

Trous coronaux

The recurring SIDC Coronal Hole 104 (polar-south, positive polarity) reached the central meridian on August 14. The SIDC Coronal Hole 116, a mid-latitude coronal hole with negative polarity, first reached the central meridian on August 15, continues its transit across the central meridian.

Vent solaire

Solar wind parameters indicate a slow solar wind regime until August 17, 04:30 UTC, after which no data are currently available. Solar wind speed varied between 307 and 400 km/s. The total interplanetary magnetic field (Bt) remained around 5 nT, and the southward interplanetary magnetic field (Bz) component fluctuated between -4.7 nT and 3.7 nT. Between August 17, 04:30 UTC and the current time (12:00 UTC), solar wind parameters are expected to remain in a slow solar wind regime under very similar conditions. The high-speed streams associated with SIDC Coronal Hole 116, a mid-latitude coronal hole with negative polarity now facing Earth, are forecast to influence solar wind conditions on August 18-19.

Géomagnétisme

Geomagnetism: Geomagnetic activity was quiet over the past 24 hours, with some periods of unsettled conditions observed locally in Belgium. NOAA Kp indices ranged between 1 and 2, and the Belgian K-index between 1 and 3. In response to the expected arrival of high-speed streams associated with SIDC Coronal Hole 116, minor geomagnetic disturbances or active conditions are possible on August 18-19.

Niveaux de flux de protons

Proton flux remained below 10 pfu over the past 24 hours, and it is expected to remain below 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 remains above the 1000 pfu threshold in response to high-speed streams associated with SIDC Coronal Hole 123 observed over the past days. Electron flux levels are expected to fluctuate around the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence remains at moderate levels and is expected to return to normal levels over the next 24 hours.

Estimation du nombre international de taches solaires (ISN) pour aujourd'hui : 084, sur la base de 21 stations.

Indices solaires pour 16 Aug 2025

Nombre de Wolf, observé par Catania	///
Flux solaire à 10 cm	122
AK Chambon La Forêt	010
AK Wingst	008
Ap estimé	007
Nombre international de taches solaires estimé	123 - Basé sur 13 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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