Archives for Tony

15 March


Solar wind speed at ACE began the period at about 450 km/s and gradually
declined to end-of-period speeds near 390 km/s. Phi was in a positive
(away) orientation through about 15/0500 UTC when a switch to a more
negative (towards) orientation occurred. Bz varied from -4 to +5 nT
early in the period. After 14/2000 UTC, Bz did not vary much beyond +/-
2 nT. Bt reached a maximum of 9 nT early in the period and remained
steady at about 5 nT for a majority of the time.

15 March


Solar activity remained at low levels. Region 2002 (S18W25,
Ehc/beta-gamma) produced a C3 x-ray flare at 15/0026 UTC. The region
exhibited penumbral growth within its intermediate spots. Region 2003
(N05W71, Eac/beta-gamma) produced a few C-class x-ray events during the
period, the largest a C5 at 15/0940 UTC. Separation and penumbra
development was observed in the region’s trailer spots resulting in an
overall increase in area. Region 2006 (N12W68, Dsi/beta) exhibited rapid
penumbra development in both the leader and trailer spots with an
increase in spot area noted. New Region 2008 (S11E79, Hsx/alpha) rotated
onto the disk. All other regions were quiet and stable. No
Earth-directed CMEs were detected.

14 March


Solar wind speed measured at the ACE spacecraft observed a steady
increase in speed from early observations near 350 km/s to end-of-period
speeds approaching 500 km/s. A brief interval from about 14/0500 – 0620
UTC observed speeds in the 525 – 625 km/s range. Bt generally ranged
between 6 – 10 nT with periods of 1 – 5 nT observed from 13/2000 – 2400
UTC. IMF Bz varied between -5 to +9 nT through about 13/2000 UTC where
it remained mostly north to +5 nT through the remainder of the period.
The Phi angle varied between positive (away) and negative (towards)
through about 14/0130 UTC when it settled into a positive orientation
for the balance of the period.

14 March


Solar activity reached moderate (R1-Minor) levels with an M1 flare at
13/1919 UTC from old Region 1996 (N16, L=051). Upon its transit around
the west limb, the region also produced a few C-class events. The
largest group on the disk remained Region 2002 (S18W11, Ehc/beta-gamma).
The region was quiet during the period and exhibited decay in its
intermediate spots with some consolidation observed in the leader
portion. The region also lost its delta magnetic configuration. Region
2003 (N06W57, Dac/beta-gamma) remained active with a few C-class events,
the largest a C4/Sf at 14/0552 UTC. The region appeared stable with no
significant changes observed. Two new regions were numbered this period;
Region 2006 (N11W54, Cao/beta) emerged on the disk while Region 2007
(N09E67, Cao/beta) rotated onto the disk. Both regions were quiet as
were the remaining spotted regions. No Earth-directed CMEs were
detected.

13 March


Solar wind parameters, as measured by the ACE spacecraft, continued to
reflect background conditions. Wind speeds ranged between 250 and 335
km/s. Total IMF (Bt) was steady between +4 to +6 nT during the first
half of the period but showed a slight increase at approximately 12/2000
UTC to +9 nT. The Bz component of the IMF reached a maximum southward
extent of -8 nT at 12/2029 UTC. The phi angle was oriented in a negative
(toward) solar sector during the period.

13 March


Solar activity increased to high levels due to an impulsive M9/Sb flare
at 12/2234 UTC from Region 1996 (N14W78, Eac/beta-gamma). Relatively
minor discrete-frequency radio bursts were associated with this flare.
Region 1996 continued its migration towards the western limb and as a
result made accurate analysis difficult. Region 2002 (S19E12,
Ekc/beta-gamma-delta) produced low-level C-class activity, showed signs
of consolidation in its intermediate spots, and maintained a visible yet
weak delta magnetic structure. Region 2003 (N06W39, Dac/beta) grew in
areal coverage but did not produce any significant flaring. Region 1999
(S16W71, Bxo/beta) was reported as a plage group yesterday but had
renewed spot emergence during the period. The remaining three sunspot
groups were stable and overall unremarkable. A full-halo, coronal mass
ejection (CME) that was first visible in LASCO/C2 imagery at 12/1448 UTC
was determined to be a backsided event and not expected to impact Earth.
There were no additional CMEs detected in satellite imagery for the
period.

12 March


Solar wind parameters, as measured by the ACE spacecraft, continued to
reflect background conditions. Wind speeds averaged near 310 km/s for
the first half of the period, then began steadily decreasing, ending the
period under 280 km/s. Total IMF (Bt) ranged between 3 and 6 nT, while
the Bz component of the IMF ranged between +/-4 nT. The phi angle began
the period in a positive (away) orientation, but quickly rotated into a
negative (toward) solar sector, where it remained for the rest of the
period.

12 March


Solar activity again reached moderate levels. Region 1996 (N14W71,
Eac/beta-gamma) was responsible for the largest flare of the period, an
impulsive M2 flare at 12/1105 UTC. This region also produced a C6/Sf at
11/2156 UTC, as well as a C7/Sf at 12/0757 UTC. Region 1996 continued to
show signs of growth as well as maintaining mix polarities near the
leader spots, though its proximity to the limb is making definite
analysis difficult. Region 2002 (S19E17, Ekc/beta-gamma) also
contributed to the flare activity, producing a C9/Sf flare at 11/1627
UTC, a C2/Sf flare at 11/2357 UTC, and a C1/Sf flare at 12/0251 UTC. The
delta magnetic configuration in this spot was not evident at the time of
this report, but has faded in and out over the past 24 hours. This
region continues to grow and is currently over 400 millionths in overall
areal coverage. Region 2003 (N06W32, Dac/beta) exhibited modest growth
over the period, yet remained fairly inactive. New Region 2005 (N11E74,
Hsx/alpha) was numbered over night. The other two numbered regions
showed signs of decay during the period. There were no Earth-directed
coronal mass ejections detected in satellite imagery during the period.

11 March


Following the onset then gradual weakening of a weak, negative-polarity
coronal hole high-speed stream (CH HSS), solar wind parameters returned
to nominal background conditions. Solar wind speed began the period near
340 km/s, but began a slow but steady decline to end the period right
around the 300 km/s mark. Total IMF (Bt) remained steady between 3 nT
and 5 nT, while Bz varied between +/-4 nT. The Phi angle held a mostly
positive (away) orientation through the majority of the period before
slowly oscillating to a slightly negative (towards) solar sector by the
end of the period.

11 March


Solar activity was moderate for the past 24 hours. Region 1996 (N13W57,
Dac/beta-gamma) produced the largest flare of the period, an M3 flare at
11/0350 UTC. It also produced an M1/Sf flare at 10/2300 UTC, as well as
several C-class flares throughout the period. This region maintained
mixed polarities in the leader spots and exhibited growth in the
intermediate spots. Region 2002 (S17E31, Dac/beta-gamma-delta) continued
to exhibit growth in its intermediate spots, new growth in the trailer
spots, as well as growth and consolidation in the leader spots. It
continues to display a delta magnetic configuration in the intermediate
spot area and exhibit overall areal growth. It was also responsible for
an M-class flare, an M1 at 10/1528 UTC, as well as a few low-level
C-class and subflares. Region 2003 (N06W17, Dao/beta), while relatively
quiet, showed signs of development in its leader spots as well as
overall areal growth. The remaining numbered sunspot regions were stable
and fairly inactive. Solar x-ray background levels have risen to mid
C-level as a result of sustained brightening on the sun’s southwest
limb. This is likely associated with an eruptive prominence on the limb
(EPL), located near S12W90. There were no Earth-directed coronal mass
ejections observed in satellite imagery.