HELIOS no. 62        13.Dec. 2000

This Helios Newsletter continues a series newsletters under the same name as above and that were issued as the newsletter of the Solar Section of the Norwegian Astronomical Society.  Helios no. 1 was issued on 2nd May 1979 and ended almost simultaneously as I resigned as the leader of that section, i.e. in August 1989.   Now I bring it to life again, started where I left it. 
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Active Regions Cycle 20 - Cycle 23

From SESC/PRF

Extracts from Preliminary Report and Forecast, SEL, Boulder, CO. USA:


SWO PRF 1306 12 September 2000
1
Space Weather Highlights SWO PRF 1306
04 – 10 September 2000 12 September 2000
Solar activity varied from low to moderate levels. Region 9154 (S19, L = 326, class/area Eki/570 on
08 September) produced an M1/1N flare at 04/0109 UTC during a period of rapid growth. Region
9154 continued to develop at a slower pace through 07 September and produced isolated C-class
subflares, then began to gradually simplify on 08 September. A 31-degree filament, last seen centered
at N13W38, disappeared during 04/0500 - 0600 UTC. SOHO/LASCO images showed a partial-halo
CME following the filament disappearance. Activity decreased to low levels during 05 - 08 September
with isolated C-class subflares from Regions 9149 (N13, L = 353, class/area Eki/380 on 1 September),
9151 (N10, L = 340, class/area Dso/110 on 08 September), and 9154. One significant event during
this low activity interval was a C7/SF flare at 07/2055 UTC associated with a Type II sweep and a
partial-halo CME. Activity returned to moderate levels on 09 September with an M1/1N flare at
09/0849 UTC from Region 9151. This flare was associated with a Type II radio sweep and a partial-halo
CME. Activity returned to low levels on the last day of the period with most sunspot groups
either stable or decaying.

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SWO PRF 1307 19 September 2000
1
Space Weather Highlights SWO PRF 1307
11-17 September 2000 19 September 2000
Solar activity varied from low to high levels. Activity was low on the first day of the period with isolated C-class
subflares. Activity increased to moderate levels on 12 September due to a long-duration M1/2N Hyder flare at
12/1213 UTC. The two-ribbon Hyder flare was associated with a 23-degree filament eruption from the south-central
portion of the disk. SOHO/LASCO images showed a halo CME following the eruption. Activity
decreased to low levels on 13 September with isolated, optically uncorrelated C-class X-ray flares. Activity
returned to moderate levels on 14 September due to an M1 X-ray flare from Region 9166 (S14, L = 124,
class/area Eai/340 on 17 September) as it rotated into view. Region 9165 (N13, L = 186, class/area Dkc/400 on
15 September) produced two M-class flares on 15 September - an M2/SF at 15/0532 UTC and an M2/1N flare
at 15/1437 UTC associated with a 190 SFU Tenflare. These flares occurred as Region 9165 was in a period of
rapid development. Activity became high on 16 September with an M5/2B flare at 16/0426 UTC from Region
9165, which had begun to decay and simplify. This flare was associated with a 1100 SFU Tenflare, Type II and
IV radio sweeps, and a halo CME. Region 9165 also produced an M3/2N at 16/1428 UTC in addition to
numerous C-class flares during the course of the day. Activity decreased to low levels on the final day of the
period due to C-class subflares, the largest of which was a C5/1F at 17/0643 UTC from Region 9167 (N12, L =
092, class/area Dso/170 on 17 September), which had rotated into view as a developing D-type spot group.

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SWO PRF 1308 26 September 2000
1
Space Weather Highlights SWO PRF 1308
18 - 24 September 2000 26 September 2000
Solar activity varied from low to high levels. Activity increased from low to high levels on 19
September due to an M5/1n flare at 19/0826 UTC from Region 9165 (N14, L = 186, class/area
Dkc/400 on 15 September). The M5 flare, which was associated with a Type II radio sweep and a 360
sfu Tenflare, occurred as Region 9165 gradually decayed. Region 9169 (N10, L = 078, class/area
Fkc/2140 on 19 September) rotated into view on 18 September as a very large, magnetically complex
sunspot group. At 2140 millionths areal coverage, Region 9169 was one of the largest sunspot groups
observed this cycle. Despite its size and complexity, it produced only isolated C-class subflares to date.
Activity was at low levels during most of the rest of the period due to isolated C-class subflares.
However, activity rose to moderate levels on 24 September due to an M4/2n flare at 24/0338 UTC
from Region 9166 (S13, L = 123, class/area Eko/760 on 21 September), which had been slowly
decaying at the time of the flare.

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SWO PRF 1309 03 October 2000
1
Space Weather Highlights SWO PRF 1309
25 September – 01 October 2000 03 October 2000
Solar activity varied from low to high levels. Activity was at moderate levels on 25 September due to
isolated, low-level M-class flares from Regions 9169 (N11, L = 078, class/area Fkc/2140 on 19
September) and 9166 (S12, L = 123, class/area Eko/760 on 21 September). Activity dropped to low
levels during 26 - 29 September with isolated to occasional C-class subflares. Activity increased to high
levels on 30 September due to an X1/Sf flare at 30/2321 UTC from Region 9169 as it was crossing the
west limb. Region 9169 also produced an M5 X-ray flare at 01/0701 UTC with an associated 200
SFU Tenflare and a loop prominence system. This large, moderately complex region had been
gradually decaying for several days prior to the major flare activity. Region 9178 (S23, L = 312,
class/area Dai/160 on 01 October) produced a long-duration M2/Sf at 01/1410 UTC as well as a C3/Sf
flare at 01/1304 UTC associated with a Type II radio sweep. Both flares occurred during a period of
growth in the region.

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SWO PRF 1310 10 October 2000
1
Space Weather Highlights SWO PRF 1310
02 - 08 October 2000 10 October 2000
Solar activity varied from low to moderate levels. Activity reached moderate levels on 02 October due
to an optically uncorrelated M1 X-ray flare at 02/0013 UTC and an M1/1n flare from Region 9177
(N29, L = 028, class/area Cao/150 on 02 October). Region 9177 was in a gradual growth phase at the
time of the flare. Activity dropped to low levels on 03 October due to occasional low-level C-class
subflares including a C1/Sf at 03/0746 UTC from Region 9177 with an associated Type II radio
sweep. Activity continued at low levels for the rest of the period with isolated B- and C-class subflares
from a few unremarkable sunspot regions.

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SWO PRF 1311 17 October 2000
1
Space Weather Highlights SWO PRF 1311
09 – 15 October 2000 17 October 2000
Solar activity varied from low to moderate levels. Activity was low during 09 - 10 October with
isolated C-class flares. Most of these flares were produced by Region 9182 (N03, L = 246, class/area
Dai/360 on 11 October) as it gradually developed, including a long-duration C6/1f flare at 09/2343
UTC with associated Type II and IV radio sweeps and a halo CME. Activity increased to moderate
levels on 12 October due to a long-duration M1/Sf flare at 12/2049 UTC from Region 9182, which
continued to gradually develop. Activity dropped to low levels on 13 October with isolated C-class
subflares. Activity returned to moderate levels on 14 October as Region 9182 produced an M1/Sf flare
at 14/0840 UTC as it was crossing the west limb. Activity decreased to low levels on the last day of
the period with isolated C-class subflares. There were two long-duration, optically uncorrelated C-class
X-ray flares detected on 15 October - a C3 at 15/0836 UTC and a C2 at 15/2212 UTC. Both
flares may have been produced beyond the west limb from old Region 9182.

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SWO PRF 1312 24 October 2000
1
Space Weather Highlights SWO PRF 1312
16 – 22 October 2000 24 October 2000
Solar activity varied from low to moderate levels. The period began with activity at moderate levels
due to a long-duration M2 X-ray flare at 16/0728 UTC with associated Type II and IV radio sweeps.
This flare likely originated from old Region 9182 (N02, L = 246, class/area Dai/360 on 11 October),
which was a day and a half beyond the west limb at the time of the flare. There was also a halo CME
associated with this flare, but it was not Earth-directed. Activity decreased to low levels during 17 - 20
October with isolated B- and C-class subflares. Activity rose to moderate levels on 21 October with an
M3/1n flare from Region 9201 (N17, L = 054, class/area Eai/250 on 22 October), which was in a
gradual growth phase at the time of the flare. Activity returned to low levels on the last day of the
period.

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SWO PRF 1313 31 October 2000
1
Space Weather Highlights SWO PRF 1313
23 - 29 October 2000 31 October 2000
Solar activity varied from low to moderate levels. Activity was low during 23 - 26 October due to
isolated C-class flares including a long-duration (approx. 7 hours) C4 X-ray flare that occurred at
25/1125 UTC from beyond the west limb. A halo-CME and a greater than 10 MeV proton event were
associated with this event. Activity increased to moderate levels for the rest of the period with isolated
low-level M-class, the largest of which was an M4/2B at 29/0157 UTC from Region 9209 (S24, L =
305, class/area Eki/300 on 29 October). This flare was associated with Type II and IV radio sweeps,
and a 9-degree

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SWO PRF 1314 07 November 2000
1
Space Weather Highlights SWO PRF 1313
30 October – 05 November 2000 07 November 2000
Solar activity was low. Isolated C-class subflares occurred from a number of largely unremarkable
sunspot groups. Events of interest included an optically uncorrelated, long-duration C2 X-ray flare at
01/1610 UTC associated with a full-halo CME, and a long-duration C3/Sf flare at 03/1902 UTC from
Region 9213 (N02, L = 270, class/area Hax/250 on 04 November), also associated with a halo CME.

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SWO PRF 1315 14 November 2000
1
Space Weather Highlights SWO PRF 1315
06 - 12 November 2000 14 November 2000
Solar activity reached high levels during the period. The week began with activity at low levels due to isolated C-class
subflares. Activity increased to moderate levels on 07 November due to an M1/1f flare at 07/1207 UTC
from Region 9213 (N02, L = 270, class/area Hax/250 on 04 November). Activity increased to high levels on 08
November due to a long-duration M7 X-ray flare at 08/2328 UTC near the northwest limb. Regions 9212 (N10,
L = 268, class/area Eso/170 on 03 November), 9213, and 9218 (N20, L = 248, class/area Eao/270 on 04
November) each produced optical flares during the M7 (the largest of which was a 3f flare from Region 9213)
making a single-point source determination difficult. A Type IV radio sweep, 710 sfu Tenflare, halo CME, and a
proton event were associated with the M7. Activity decreased to moderate levels on 09 November with optically
uncorrelated M1 X-ray flares at 09/0314 UTC and 09/0610 UTC, and an M1/Sf flare at 09/1613 UTC from
Region 9221 (S12, L = 175, class/area Dao/120 on 06 November). Activity decreased to low levels during 10 -
12 November due to isolated to occasional C-class subflares.

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SWO PRF 1316 21 November 2000
1
Space Weather Highlights SWO PRF 1316
13 - 19 November 2000 21 November 2000
Solar activity reached moderate levels twice during the period. The week began with activity at low
levels due to isolated C-class subflares. Activity increased to moderate levels on 14 November due to
an optically uncorrelated M1 X-ray flare at 14/1634 UTC. Region 9231 (S23, L = 056, class/area
Dao/140 on 14 November) produced a C7/2n flare at 14/0806 UTC. A Type IV radio sweep is
believed to have been associated with the C7. A Type II radio sweep occurred at 14/0902 UTC.
Activity decreased to low levels during 15 - 17 November due to isolated to occasional C-class
subflares. An impressive full-halo CME occurred early on 16 November but was judged to be from a
source on the far side of the Sun. A C8 X-ray flare occurred at 16/0400 UTC associated with a Type
II radio sweep and a CME determined to be not Earth-directed. Activity reached moderate levels once
again on 18 November due to an M1/1f flare at 18/1325 UTC from Region 9235 (N14, L = 025,
class/area Dso/140 on 18 November). A Type II radio sweep and a CME (not Earth-directed) was
associated with this event. Region 9231 (S24, L = 057, class/area Fai/330 on 18 November) produced
an M1/Sf flare at 18/1100 UTC. Activity decreased to low levels on 19 November due to occasional
C-class subflares.

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SWO PRF 1317 28 November 2000
1
Space Weather Highlights SWO PRF 1317
20 - 26 November 2000 28 November 2000
Solar activity reached high levels during the period. The week began with activity at low levels due to
isolated C-class subflares. Activity increased to moderate levels on 21 November due to an M1/Sn flare
at 21/1921 UTC from Region 9231 (S23, L = 058, class/area Fki/410 on 20 November). Activity
decreased to low levels on 22 November with occasional C-class subflares from Region 9236 (N20, L
= 352, class/area Eki/600 on 26 November), which showed rapid development in area and magnetic
complexity. Activity increased to moderate levels on 23 November due to an M1/Sf flare from Region
9236 at 23/2328 UTC associated with a Type II radio sweep. Activity increased to high levels during
the remainder of the period as Region 9236 produced a series of X-class flares, three of which
occurred on 24 November. The first was an X2/3b at 24/0502 UTC associated with a 2200 sfu
Tenflare, a Type II radio sweep, a halo CME, and a solar proton event (see the discussion below). This
was followed by an X2/2b at 24/1513 UTC which was accompanied by a Type II sweep and a halo
CME. The third was an X1/2n at 24/2159 UTC associated with a CME. Region 9240 (N09, L = 296,
class/area Dho/300 on 26 November) added to the major flare count with an M8/2n at 25/0131 UTC
associated with an 11,000 sfu tenflare, and Type II and IV radio sweeps. Region 9236 produced an
X1/2b flare at 25/1844 UTC associated with an 1100 sfu Tenflare, Type II radio sweep, and a halo
CME. Region 9236 appeared to stabilize on 26 November as a large, magnetically complex F-type
group, but managed to produce an X4/2b flare at 26/1648 UTC associated with a 700 sfu Tenflare and
a Type II sweep. Region 9236 began to show signs of gradual decay as the period ended, but it
remained large and magnetically complex.

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SWO PRF 1318 05 December 2000
1
Space Weather Highlights SWO PRF 1318
27 – November – 03 December 2000 28 November 2000
Solar activity was at low to moderate levels. Activity was at low levels during 27 - 29 November due
to C-class flares from a few regions of moderate size and complexity. Flare producing regions of note
included Region 9236 (N20, L = 352, class/area Eko/630 on 27 November), which was responsible for
last week's major flare activity, and Region 9246 (S12, L = 248, class/area Eai/220 on 30 November).
Region 9236 was large and magnetically complex, but slowly decayed before making an uneventful
west limb passage on 30 November. Region 9246 was moderate in size and magnetic complexity and
in a development phase until 01 December, then stabilized. It produced a C9/Sf flare at 29/0629
UTC with an associated Type II radio sweep. Activity rose to moderate levels on 30 November as
Region 9246 produced an M1/Sf flare at 30/2038 UTC. It may have also been responsible for an
optically uncorrelated M1 X-ray flare at 30/0925 UTC. Activity was low during the rest of the period
due to isolated C-class X-ray flares, most of which were optically uncorrelated.

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SWO PRF 1319 12 December 2000
1
Space Weather Highlights SWO PRF 1319
04 - 10 December 2000 12 December 2000
Solar activity ranged from very low to moderate levels. The period began with activity at very low
levels. Activity increased to low levels on 05 December with isolated low-level C-class subflares. A
further increase to moderate levels occurred on 06 December by virtue of an isolated M1/Sf flare at
06/2230 UTC from Region 9246 (S12, L = 248, class/area Eao/250 on 07 December). Region 9246
was of moderate size and magnetic complexity, but gradually decaying at the time of this flare. Solar
activity dropped to low levels for the rest of the period due to isolated to occasional C-class subflares.
The visible regions were either stable or declining at the close of the summary period.
Data were available from the Advanced Composition Explorer (ACE) spacecraft for most of the
period. Solar wind conditions were largely unremarkable through 06 December with the exception of a
few periods of sustained southward IMF Bz with deflections to minus 09 nT (GSM). A recurrent
coronal hole wind stream began on 07 December and continued through the rest of the period with
velocities peaking at 710 km/sec during 09 - 10 December.
There were no proton events detected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit was at normal to moderate levels.
The geomagnetic field was at mostly quiet to unsettled levels during 4 - 7 December with isolated
active periods. The field was disturbed during 8 - 9 December due to a high speed stream associated
with a recurrent, negative polarity coronal hole. Unsettled to active levels occurred during this period
with brief minor to major storm intervals detected at some high latitude stations. Activity subsided to
quiet to unsettled levels on the last day of the period.
Space Weather Outlook
13 December - 08 January 2001
Solar activity is expected to be at low to moderate levels. An increasing trend is expected to begin 13
December with the return of previously active longitudes. There will also be a chance for a major flare
during the first half of the period.
Chances for a proton event are expected to increase during the first half of the period due to the return
of previously active longitudes.
The greater than 2 MeV electron flux at geosynchronous orbit may reach moderate to high levels
during 05 - 06 January. Otherwise, normal to moderate fluxes are expected.
Active levels will be possible around 04 - 05 January due to coronal hole effects. Quiet to unsettled
levels are expected during the rest of the period, barring an Earth-directed CME.

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NOTE!
Most likely the Solar Maximum Cycle 23
occurred 10th August 2000
(peak Smoothed 24wk CV: )

There are 6 New members since 01. Sep. 2000:

We wish you all welcome!

Helios no. 63 will be issued 01. Mar. 2001

CV-Helios Network 14 des 2000