Affichage des archives de mardi, 26 août 2014

Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2014 Aug 26 1243 UTC

Prévisions SIDC

Éruptions solaires

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

Géomagnétisme

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

Moniteur de Flux de Proton

Warning condition (activity levels expected to increase, but no numeric forecast given)

	Flux de 10 cm	Ap
26 Aug 2014	142	009
27 Aug 2014	142	011
28 Aug 2014	142	014

Bulletin

Flaring activity continued at the same level with four C- and two M-class flares, originating from NOAA AR 2146. Two CMEs were observed in coronographic imagery, with NOAA AR 2146 as source region. An asymmetric halo CME was visible in SOHO/LASCO C2 and C3 and STEREO B/COR2 data, with first measurements on August 25 at 15:24 UT (C2), 16:18 UT (C3) and 16:24 UT (STEREO B) respectively. The CME was associated with a M2 flare peaking at 15:11 UT, dimming and type II and IV radio bursts (shock speed estimated at 707 km/s by the Sagamore Hill station). The CME has a projected line-of-sight speed of 568 km/s (CACTus estimate). A second partial halo CME was visible in SOHO/LASCO C2 and C3, with first measurements on August 25 at 20:36 UT (C2) and 21:18 UT (C3). Also this CME was associated with an M-class flare (M3.9, peak at 20:21 UT). The CME is travelling with a projected line-of-sight speed of 761 km/s (CACTus estimate). Both CMEs are mainly propagating in the western direction from the Sun-Earth line and might be interacting with each other. A shock might arrive in the second half of the UT day of August 28. More C- and M-class flares are expected, especially from NOAA ARs 2146 and 2149. An X-class flare is possible, but unlikely. Proton flux levels at > 10MeV have increased from 18:00 UT on, but remained below the event threshold and are currently decreasing. A warning condition for a proton event, in case of more flaring, is issued. Solar wind speed slightly increased from 250 till 290 km/s. The amplitude of the interplanetary magnetic field increased to 7 nT, with a varying Bz component. Geomagnetic conditions were quiet to unsettled and are expected to remain so until the combined arrival of the August 22 CME's. This may potentially result in active geomagnetic conditions from the afternoon of August 26 onwards.

Estimation du nombre international de taches solaires (ISN) pour aujourd'hui : 070, sur la base de 07 stations.

Indices solaires pour 25 Aug 2014

Nombre de Wolf, observé par Catania	///
Flux solaire à 10 cm	135
AK Chambon La Forêt	005
AK Wingst	003
Ap estimé	003
Nombre international de taches solaires estimé	087 - Basé sur 17 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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