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Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2025 May 02 1238 UTC

Prévisions SIDC

Éruptions solaires

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

Géomagnétisme

Minor storm expected (A>=30 or K=5)

Moniteur de Flux de Proton

Quiet

	Flux de 10 cm	Ap
02 May 2025	154	031
03 May 2025	154	022
04 May 2025	154	012

Régions solaires actives et éruptions solaires

Solar flaring activity was low over the past 24 hours, with only C-class flares detected. The number of visible sunspot groups continues to decline, with just two currently observed on the solar disk. SIDC Sunspot Group 469 (NOAA Active Region 4079), currently located at N08E37, continues to grow and now exhibits a Beta-Gamma-Delta magnetic configuration. This region was responsible for all the C-class flares recorded during the period. The other region, SIDC Sunspot Group 459 (NOAA Active Region 4076), is small, has an Alpha magnetic configuration, and did not produce any flaring activity. Solar flaring activity is expected to remain low to moderate over the next 24 hours, with C-class flares likely and a chance of M-class flares from SIDC Sunspot Group 469 (NOAA Active Region 4079), which continues to develop.

Éjection de masse coronale

Several filaments are visible on the solar disk; however, they appear stable at this time. No Earth-directed coronal mass ejections (CMEs) were observed in the available coronagraph imagery over the past 24 hours.

Trous coronaux

SIDC Coronal Hole 99, a trans-equatorial coronal hole with negative polarity, crossed the central meridian on April 29 and is now positioned on the western side of the Sun. The associated high-speed solar wind stream is currently affecting Earth. Two small coronal holes that reached the central meridian on May 1 (SIDC Coronal Hole 109, an equatorial coronal hole with negative polarity, and SIDC Coronal Hole 110, a high- latitude northern coronal hole also with negative polarity) have now also shifted to the western side of the Sun. Additionally, a new small coronal hole, SIDC Coronal Hole 111, has emerged in the southern high latitudes on the eastern side of the Sun. It is also characterized by negative polarity.

Vent solaire

The Earth is currently under the influence of an enhanced solar wind stream, with speeds increasing and currently ranging between 550 and 670 km/s. The total interplanetary magnetic field (IMF) remains elevated, reaching a maximum of 14.5 nT. The southward component of the IMF (Bz) has remained mostly negative, with a minimum value of -13.1 nT recorded. The phi angle continues to indicate a negative sector, confirming the ongoing magnetic connection to the high-speed solar wind stream associated with SIDC Coronal Hole 99 (a large trans-equatorial coronal hole with negative polarity). These conditions are expected to persist for the next few days as the influence of this coronal hole continues. Looking ahead, in approximately two days, following a brief period of relative calm, solar wind speeds may once again increase. This would be due to the expected influence of two smaller coronal holes that crossed the central meridian on May 1: SIDC Coronal Hole 109, an equatorial coronal hole with negative polarity, and SIDC Coronal Hole 110, a high-latitude northern coronal hole also with negative polarity.

Géomagnétisme

Geomagnetic conditions have intensified, with Kp-NOAA reaching 5+ and K_BEL reaching 4, indicating the onset of a minor geomagnetic storm. This elevated activity is driven by the ongoing influence of a high-speed solar wind stream originating from SIDC Coronal Hole 99 (a large, elongated trans-equatorial coronal hole with negative polarity that crossed the central meridian on April 29) and by the interplanetary magnetic field's Bz component, which has remained primarily negative throughout the period. Active conditions are expected to persist over the next 24 hours, with possible fluctuations between active and minor storm levels, before gradually easing as the influence of the high-speed stream diminishes.

Niveaux de flux de protons

No enhancement or solar energetic particle event has been detected over the past 24 hours. The greater-than-10 MeV proton flux remained at low levels over the past 24 hours and is expected to stay below the event threshold in 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 remained below the threshold level over the past 24 hours. However, the flux may increase and exceed the threshold in the next 24 hours in response to the ongoing high-speed solar wind stream currently affecting Earth. The 24-hour electron fluence remains at normal levels and is expected to stay stable in the short term, though it may become elevated and reach moderate levels due to the ongoing solar wind conditions.

Estimation du nombre international de taches solaires (ISN) pour aujourd'hui : 043, sur la base de 22 stations.

Indices solaires pour 01 May 2025

Nombre de Wolf, observé par Catania	///
Flux solaire à 10 cm	152
AK Chambon La Forêt	043
AK Wingst	031
Ap estimé	031
Nombre international de taches solaires estimé	069 - Basé sur 24 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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