SIDC Weekly Bulletin

Issued: 2020 Sep 07 1342 UTC
Product: documentation at www.sidc.be/products/bul
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SIDC Weekly bulletin on Solar and Geomagnetic activity #

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WEEK 1027 from 2020 Aug 31
SOLAR ACTIVITY
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Solar activity was at very low levels with the solar X-ray flux below B-level throughout the week.

There were no Earth-directed coronal mass ejections observed in coronagraph data.

The greater than 10 MeV proton flux was at background levels.
The greater than 2 MeV electron flux was at Moderate to High levels for the entire week in response to the enhanced solar wind conditions, reaching a maximum value of 29400 pfu at 16:20 UT Sep 02.
GEOMAGNETIC ACTIVITY
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The solar wind parameters were enhanced at the start of the week due to the influence of the positive polarity coronal hole that crossed central meridian on August 28. The solar wind speed was around 500 km/s at the start of the week and Increased from Aug 31 to Sep 01, reaching a maximum value of around 640 km/s on Sep 01. The speed then slowly decreased over the rest of the week to values just less than 400 km/s on Sep 06. The total magnetic field ranged between 0 and 9 nT and Bz had a minimum value of -7 nT. The interplanetary magnetic field (phi angle) was predominantly directed away from the Sun (positive sector).

Geomagnetic conditions reached active to minor storm levels (NOAA Kp 3-5 and local K Dourbes 2-4) on Aug 31 to Sep 01 due to the influence of the High-speed stream from the positive polarity coronal hole. From Sep 02 to Sep 06 geomagnetic conditions became mostly quiet with a few unsettled intervals (NOAA Kp and local K Dourbes 0-3) in response to the decreasing solar wind speed.
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DAILY INDICES
DATE RC EISN 10CM Ak BKG M X
2020 Aug 31 000 /// 070 028 A1.1 0 0
2020 Sep 01 000 000 070 023 A1.1 0 0
2020 Sep 02 /// 000 068 012 A1.8 0 0
2020 Sep 03 /// 000 070 /// A1.6 0 0
2020 Sep 04 000 000 070 008 A1.4 0 0
2020 Sep 05 /// 000 069 006 A1.0 0 0
2020 Sep 06 /// 000 070 005 A1.2 0 0
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RC : Sunspot index (Wolf Number) from Catania Observatory (Italy)

EISN : Estimated International Sunspot Number

10cm : 10.7 cm radioflux (DRAO, Canada)

Ak : Ak Index Wingst (Germany)

BKG : Background GOES X-ray level (NOAA, USA)

M,X : Number of X-ray flares in M and X class, see below (NOAA, USA)

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NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX END LOC XRAY OP 10CM Catania/NOAA RADIO_BURST_TYPES
NONE

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