Viewing archive of Tuesday, 17 October 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Oct 17 1236 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
17 Oct 2023	145	001
18 Oct 2023	146	010
19 Oct 2023	146	007

Solar Active Regions and flaring

The solar flaring activity was at low levels. There are currently five numbered active regions on the solar disk, with a new, as yet unnumbered region, that has rotated over the north east limb. This region was associated with largest flare of the period, an impulsive C9.8 flare. NOAA AR3463 also produced a number of low-level C-class flares, including a long duration C2 flare at 05:05 UTC, but has since decayed. NOAA AR 3465 showed some flux emergence while NOAA AR3466 decayed into a plage region. The remaining regions were mostly simple and were quiet. The solar flaring activity is expected to be at low levels over the next 24 hours with C-class flares likely and a low chance for isolated M-class flares.

Coronal mass ejections

A Coronal Mass Ejection (CME) to the east was observed in SOHO/LASCO-C2 data from 11:48 UTC. This was associated with a long duration C7.5 flare on October 16, peaking at 10:51 UTC. The CME appears to mostly be directed to the east but a wider shock is visible. A glancing blow at Earth is possible on October 20. Another CME, first observed from 05:17 UTC in SOHO/LASCO-C2 to the south west, was associated with the long duration C2 flare from NOAA3463. Due to the location of the CME source, this may have an Earth directed component and analysis is ongoing.

Solar wind

The solar wind parameters reflected a slow solar wind regime The interplanetary magnetic field ranged between 1 and 3nT. Bz had a minimum value of -2 nT. The solar wind speed decreased further from 360 km/s to 300 km/s. The interplanetary magnetic field orientation was predominantly in the negative sector (field directed towards the Sun). The solar wind parameters are expected to reflect nominal conditions for the next days, with possible slight enhancements in the solar wind speed from October 18 due to the solar wind associated with the positive polarity coronal hole which crossed the central meridian on October 14.

Geomagnetism

During last 24 hours the geomagnetic conditions were at quiet levels (NOAA KP and K Bel 1-2). Geomagnetic conditions are expected to be at quiet to unsettled levels on October 17, with isolated active conditions possible from October 18.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux was at nominal levels and is expected to remain so over the next days.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux remained below the 1000 pfu threshold as measured by GOES 16. It is expected to remain below this threshold over the next days. The 24 hour electron fluence was at nominal levels. The electron fluence is expected to be at nominal levels for the next days.

Today's estimated international sunspot number (ISN): 077, based on 19 stations.

Solar indices for 16 Oct 2023

Wolf number Catania	147
10cm solar flux	144
AK Chambon La Forêt	005
AK Wingst	002
Estimated Ap	002
Estimated international sunspot number	095 - Based on 29 stations

Noticeable events summary

Provided by the Solar Influences Data analysis Center© - SIDC - Processed by SpaceWeatherLive

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