Archives for Tony

2nd September


Solar activity was at low levels. Region 2152 (S16W05,
Eac/beta-gamma)produced a C2/Sf flare at 02/0059 UTC, the largest flare
of the period, as well as other low level C-class flares. This region
continued to grow, primarily in its intermediate spot area. Region 2153
(S10W31, Dao/beta) also grew significantly during the period, mainly in
its leader spot area. The remaining spot groups were stable and appeared
to be fairly stable.

A Type II radio sweep (estimated velocity 1,094 km/s) was observed at
01/2211 UTC along with a Type IV sweep associated with an eruption off
the east limb. No flare accompanied the event and the resulting CME
appears to be headed well east of the Sun-Earth line. Two additional
CMEs were observed in Lasco C2 imagery departing the east limb. The
first became visible at 01/2224 UTC, with the second one first showing
at 02/0236 UTC. Both appear to have an eastward trajectory, resulting in
likely non-Earth directed CMEs. There was also a faint, partial halo CME
that became visible in the Lasco C2 imagery at approximately 01/2136
UTC. This CME had a mostly northwesterly trajectory, but will be modeled
as soon as imagery is available.

The other notable feature on the visible disk was a nearly 38 degree
long filament, centered near N19W10, that appeared to be beginning to
lift off from the corona. At the time of this discussion, it had not
erupted nor lifted off, but will be monitored closely.

1st September


Solar wind parameters at ACE were indicative of a continued coronal hole
high speed stream (CH HSS) solar wind regime. Solar wind speeds were
relatively steady between 400-450 km/s. IMF total field values were
steady near 4-7 nT and Bz was predominately southward throughout the
period. The phi angle remained stable in a positive (away) sector
throughout the period.

1st September


Solar activity remained at low levels. Region 2149 (N09W70, Dkc/beta)
was the prominent flare producer this period. Region 2149 produced a C7
flare at 31/1211 UTC which was the largest event of the period. In
addition to numerous low-level C-class flares, Region 2149 produced a
long duration C2/Sf flare at 01/0744 UTC. A Type-II radio emission at
01/1113 UTC with an estimated velocity of 2,079 km/s is believed to be
associated with activity behind the east limb.

Region 2149 continued to exhibit a minor trend of penumbral decay as it
approaches the west limb. Region 2152 (S16E08, Dac/beta-gamma) also
began a trend of decay but maintained a weak beta-gamma magnetic
configuration. Region 2153 (S10W17, Cao/beta) showed signs of
development in its trailer spot area early in the period but, along with
the other regions on the visible disk, was relatively stable throughout
the remainder of the period.

A coronal mass ejection (CME) associated with the long duration C2/Sf
flare from Region 2149 at 01/0744 UTC was observed off the northwest
limb in SOHO/LASCO C2 coronagraph imagery beginning at 01/0924 UTC.
Additional imagery and analysis is needed to determine if this CME has
an Earth-directed component. At the time of this writing, no
Earth-directed CMEs were observed.

31st August


Solar wind parameters are ACE were indicative of a continued coronal
hole high speed stream (CH HSS) solar wind regime. Solar wind speeds
were steady in the 380-420 km/s range. IMF total field values were
steady near 5-7 nT and Bz briefly reached a maximum southward component
of -7 nT late in the period. The phi angle was predominately steady in
a positive (away) sector with brief periods of transition to a negative
(toward) sector late in the period.

31st August


Solar activity was low. Region 2149 (N10W55, Dkc/beta) produced several
C-class flares this period this period, the largest of which was a
long-duration C3 flare at 31/1118 UTC. Region 2149 initially showed
signs of minor penumbral decay but began to redevelop late in the
period. Region 2152 (S17E21, Dai/beta-gamma) continued a trend of
overall growth this period and contributed a few low-level C-class
flares.

No Earth-directed coronal mass ejections (CMEs) were observed this
period.

30th August


Solar wind parameters at ACE were indicative of continued coronal hole
high speed stream (CH HSS) effects. Solar wind speeds were relatively
steady in the 400-450 km/s range. IMF total field values were steady
near 5-7 nT and Bz varied between +7 nT and -7 nt. The phi angle was
predominately stable in a positive (away) sector throughout the period,
but showed some deviation to a negative (toward) sector early in the
period.

30th August


Solar activity was low. Regions 2149 (N10W43, Dhc/beta) and 2152
(S17E34, Dao/beta) each produced several low-level C-class flares this
period, the largest of which was a C4 flare from 2149 at 29/1552 UTC.

Region 2149 began to show signs of weakening late in the period while
Region 2152 exhibited a moderate growth trend. The other regions on the
visible disk were relatively stable throughout the period.

No Earth-directed coronal mass ejections (CMEs) were observed.

29th August


Solar wind parameters at ACE were indicative of coronal hole high speed
stream (CH HSS) effects in addition to waning CME influence. Solar wind
speeds increased from initial values near 350 km/s to end-of-period
values near 440 km/s. IMF total field values reached a maximum of 11 nT
and Bz reached a maximum southward component of -10 nT. The phi angle
was steady in a positive (away) sector orientation throughout the
period.

29th August


Solar activity was low. Region 2146 (N08, L=347) produced a pair of C1
flares at 28/1520 and 29/0226 UTC and continued to rotate behind the
west limb this period.

Region 2149 (N10W29, Cso/beta) showed rapid development south of its
main spot area late in the period. New Region 2153 (S11E25, Axx/alpha)
was numbered this period but was otherwise unremarkable. The other
regions on the visible disk were either stable or in decay.

No coronal mass ejections (CMEs) were observed this period.

28th August


The solar wind environment at the ACE spacecraft continued to reflect
the CME passage. Early in the period, the wind speed rose from 300 to
near 350 km/s and it remained in the upper 300 km/s range. Bt remained
elevated, nearing 14 nT and ending near 10 nT. Bz was negative for the
bulk of the period, dipping to -14 nT and ending near -8 nT. Phi was
generally positive.