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:Product: 7-day Space Weather Highlights
:Issued: 2014 Sep 22 0605 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# http://www.swpc.noaa.gov/wwire.html
#
#                7-day Space Weather Highlights
#
Highlights of Solar and Geomagnetic Activity
15 - 21 September 2014

Solar activity ranged from low to moderate levels during the period.
Low levels were reached on 15-17 September and again on 19-21
September with moderate activity observed on 18 September. A
majority of the early C-class activity was observed from Regions
2158 (N16, L=087, class/area Dkc/440 on 11 Sep) and 2164 (S14,
L=049, class/area Dai/090 on 14 Sep). The largest of these C-class
events was a C7 X-ray event observed at 17/1948 UTC from Region
2158.

By 18 September, activity increased to moderate levels. At 18/0709
UTC, Region 2169 (N05, L=290, class/area Cso/060 on 17 Sep) produced
a C6/Sf which was immediately followed by an impulsive M1/Sn
(R1-Minor) at 18/0841 UTC from the same region. Associated with this
event were lower frequency radio emissions in the form of a Type II
sweep and 245 MHz burst (16,000 sfu). An associated CME was not
discernable in LASCO or STEREO imagery with the M1 event.

19-21 September saw a return to low levels with C-class activity
observed from Regions 2164, 2166 (N13, L=352, class/area Dao/060 on
14 Sep), 2171 (S10, L=264, class/area Eai/160 on 21 Sep) and 2172
(S11, L=242, class/area Ekc/320 on 21 Sep). The largest event during
this 3-day period was a long-duration C5/1f flare at 21/1153 UTC
from Region 2166. This region had decayed to plage on 20 September.
Associated with this event was a CME off the NW limb, detected by
LASCO C2 imagery, first visible at 21/1236 UTC. Potential
geo-effectiveness of this CME was ongoing at the time of this
writing.

Other activity of note during the period was a N-S oriented, 38
degree long filament eruption along a channel centered near N25E12.
The filament was observed lifting off in SDO/AIA 304 imagery from
20/2348-21/0427 UTC. No discernable CME was apparent in LASCO or
STEREO imagery with the filament eruption.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was
normal levels.

Geomagnetic field activity ranged from quiet to minor storm levels.
Mostly quiet levels were observed from 15 September through late on
18 September. By 18/1800 UTC, field activity increased to unsettled
levels for six hours and further increased to active to minor
storming through 21/0900 UTC. The field relaxed to unsettled to
active levels through 21/2100 UTC when it became predominately quiet
through the balance of the summary period. This period of increased
activity was attributed to a combination of transient and negative
coronal hole high speed stream (CH HSS) effects.

During the summary period, solar wind parameters, as observed at the
ACE spacecraft, reflected the geomagnetic activity described above.
ACE wind speeds began the period in the 450 km/s range and gradually
decreased to near 350 km/s through early on 19 September. Wind
speeds then increased to about 500 km/s by late on the 19th and
further increased to 550 km/s by midday on 20 September and remained
elevated through midday on the 21st. Speeds then declined to end the
summary period near 425 km/s.

The interplanetary magnetic field (IMF) Bt and Bz component followed
a similar trend. Bt varied weakly from 3-7 nT through about 19/0600
UTC when an increase to 10-18 nT was observed for the next 9 hours
or so. Bt gradually relaxed to vary between 4-8 nT through the
remainder of the period. The Bz component generally did not vary
much beyond -5 to +8 nT through the summary period. The exception
was a period between 19/0400-1700 UTC when Bz varied between -13 nT
to +17 nT.

Phi angle measurements indicated a predominately negative (towards)
orientation with positive (away) swings from about 18/1800 UTC -
19/1700 UTC and again from 21/0300 UTC - 21/1700 UTC.


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