Affichage des archives de lundi, 28 septembre 2020

Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2020 Sep 28 1230 UTC

Prévisions SIDC

Éruptions solaires

Quiet conditions (<50% probability of C-class flares)

Géomagnétisme

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

Moniteur de Flux de Proton

Quiet

	Flux de 10 cm	Ap
28 Sep 2020	073	028
29 Sep 2020	072	020
30 Sep 2020	072	009

Bulletin

The solar activity was at very low levels with no significant flares. There are no sunspots on the solar disk and no significant flares are expected over the next 24 hours.

No Earth-directed Coronal Mass Ejections (CMEs) were observed in the available coronagraph imagery.

The greater than 10 MeV proton flux was at nominal levels in the past 24 hours, and is expected to remain so in the next 24 hours. The greater than 2 MeV electron flux was oscillating at moderate levels, exceeding the 10^3 pfu threshold between 07:55 and 10:00 UT today. The electron flux is expected to remain elevated over the next 24 hours.

Over the past 24 hours the solar wind conditions were elevated due to the arrival of a high-speed stream, associated with a positive polarity northern coronal hole, which crossed the central meridian on Sept 26th. According to ACE and DSCOVR data, the total interplanetary magnetic field varied between 1 nT and 10 nT. The north-south Bz component fluctuated between -9 nT and 8 nT, with highest absolute value around 19:00 UT on Sept 27th. The Phi angle was predominantly positive reflecting the influence of the positive-polarity coronal hole. In the past 24 hours the solar wind speed was enhanced with values between 433 km/s and 660 km/s. A prolonged period of fast stream with speed exceeding 600 km/s was observed around 18:30 UT on Sept 27th and continues at present. The solar wind conditions are expected to remain enhanced over the next 24 hours.

Over the past 24 hours the geomagnetic conditions have globally reached moderate storm levels with planetary index Kp equal to 6 between 21:00 UT and midnight on Sept 27th, and locally minor storm levels with K Dourbes equal to 5. We are currently under the influence of the fast solar wind stream originating from the positive-polarity low-latitude large-area coronal hole which is now connected to the northern polar coronal hole and partially still residing on the central meridian. This influence is expected to continue in the following 2 to 3 days. Over the next 48 hours we expect active conditions with periods of minor geomagnetic storms. Isolated periods of moderate storms remain possible.

Estimation du nombre international de taches solaires (ISN) pour aujourd'hui : 000, sur la base de 10 stations.

Indices solaires pour 27 Sep 2020

Nombre de Wolf, observé par Catania	///
Flux solaire à 10 cm	074
AK Chambon La Forêt	042
AK Wingst	021
Ap estimé	024
Nombre international de taches solaires estimé	000 - Basé sur 21 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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