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Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2025 May 20 1231 UTC

Prévisions SIDC

Éruptions solaires

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

Géomagnétisme

Active conditions expected (A>=20 or K=4)

Moniteur de Flux de Proton

Quiet

	Flux de 10 cm	Ap
20 May 2025	118	013
21 May 2025	119	013
22 May 2025	120	015

Régions solaires actives et éruptions solaires

Solar flaring activity over the last 24 hours has been low, with only a few C-class flares. The strongest flare was a C5.3 flare peaking at 05:54 UTC on May 20, associated with SIDC Sunspot Group 503 (magnetic type beta). There are currently seven numbered active regions on the solar disk. The most complex one is SIDC Sunspot Group 496 (NOAA Active Region 4087, magnetic type beta-delta). SIDC Sunspot Groups 502 and 503 (both magnetic type beta) have rotated on disk from the east limb, in the southeast quadrant. Solar flaring activity is expected to be low over the next 24 hours, with C-class flares expected and a small chance for M-class flares.

Éjection de masse coronale

A faint prominence eruption was observed in SDO/AIA 304 data around 07:40 UTC on May 20, over the northeast limb. A filament eruption was observed in SDO/AIA 304 data around 08:00 UTC on May 20, west of SIDC Sunspot Group 496 (NOAA Active Region 4087). No associated Coronal Mass Ejection (CME) was observed for either event in the available coronagraph imagery. No other Earth-directed CMEs were observed in the available coronagraph imagery.

Trous coronaux

The elongated, mid-latitude, positive polarity coronal hole (SIDC Coronal Hole 104) continues to cross the central meridian since May 15.

Vent solaire

The solar wind conditions (ACE and DSCOVR) were enhanced during the past 24 hours, most likely due to the continuous influence of a high- speed stream from the southern, positive polarity coronal hole (SIDC Coronal Hole 104). The solar wind speed ranged between 480 km/s and 550 km/s. The interplanetary magnetic field values increased from 5 nT to 9 nT. The Bz component ranged between -8 nT and 7 nT. The interplanetary magnetic field angle phi was predominantly in the positive sector. Further enhancements in the solar wind conditions may be expected over the next 24 hours, under the continuous influence of the high-speed stream from the southern, positive polarity coronal hole (SIDC Coronal Hole 104).

Géomagnétisme

Geomagnetic conditions globally were initially at quiet levels (NOAA Kp 2- to 2+) over the past 24 hours, reaching unsettled levels (NOAA Kp 3) between 03:00 UTC and 12:00 UTC on May 20. Geomagnetic conditions locally were mostly at quiet levels (K BEL 2), with a few intervals of unsettled levels (K BEL 3). Mostly unsettled to active levels, with a small chance for isolated minor storm intervals (NOAA Kp 3 to 5, K BEL 3 to 5), are expected over the next 24 hours, under the continuous influence of the high-speed stream from the southern, positive polarity coronal hole (SIDC Coronal Hole 104).

Niveaux de flux de protons

The greater than 10 MeV proton flux was below the 10 pfu threshold over the past 24 hours. It is expected to remain below the threshold level over the next 24 hours.

Flux d'électrons sur l'orbite géostationnaire

The greater than 2 MeV electron flux measured by GOES 18 was over the 1000 pfu threshold between 14:50 UTC on May 19 and 03:40 UTC on May 20. The greater than 2 MeV electron flux measured by GOES 19 was over the 1000 pfu threshold between 14:00 UTC and 23:50 UTC on May 19. The greater than 2 MeV electron flux is expected to be above the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence is presently at normal levels but is expected to gradually increase over the next 24 hours.

Estimation du nombre international de taches solaires (ISN) pour aujourd'hui : 082, sur la base de 20 stations.

Indices solaires pour 19 May 2025

Nombre de Wolf, observé par Catania	084
Flux solaire à 10 cm	117
AK Chambon La Forêt	014
AK Wingst	014
Ap estimé	013
Nombre international de taches solaires estimé	071 - 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

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