HELIOS-61

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.
Comments? Post them!

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

SWO PRF 1286 25 April 2000
1
Space Weather Highlights SWO PRF 1286
17 - 23 April 2000 25 April 2000
Solar activity was low. C-class flares occurred daily. The week's principal flare producer was Region
8963 (N16, L = 002, class/area Dao/080 on 18 April), a relatively small, mixed-polarity region. This
region showed minor growth through 20 April, then slowly decayed. One event of note from Region
8963 was a C4 x-ray flare at 18/1153UT with an associated Type II radio sweep.

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SWO PRF 1287 02 May 2000
1
Space Weather Highlights SWO PRF 1287
24 - 30 April 2000 02 May 2000
Solar activity was low. C-class flares occurred daily. There were two flares of interest during the
period: a C5/1N at 28/1851UT with an associated Type II radio sweep (estimated velocity 500
km/sec) from Region 8967 (N22, L = 296, class/area Eao/220 on 22 April) and a C7/1N at
30/0808UT, also associated with a Type II radio sweep (estimated velocity 700 km/sec), from Region
8976 (S11, L = 236, class/area Dao/060 on 29 April).

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SWO PRF 1288 09 May 2000
1
Space Weather Highlights SWO PRF 1288
01 - 07 May 2000 09 May 2000
Solar activity ranged from very low to high levels. Activity was at moderate levels through 03 May by
virtue of isolated low-level M-class flares, mostly from Regions 8970 (S14, L = 262, class/area
Ekc/1210 on 23 April) and 8971 (N18, L = 264, class/area Eko/910 on 24April). Both regions were
large with a minor degree of magnetic complexity and showed gradual decay before crossing the west
limb on 03 May. Activity increased to high levels on 04 May due to an M6 x-ray flare from behind the
west limb at 04/1108UT. Old Region 8970 was the likely source for this event. The same was true for
a long-duration M1 x-ray flare observed at 05/1621UT. Activity dropped to very low levels during the
last two days of the period.

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SWO PRF 1289 16 May 2000
1
Space Weather Highlights SWO PRF 1289
08 - 14 May 2000 16 May 2000
Solar activity ranged from low to moderate levels. Activity was low during 08-11 May. However,
there were a few interesting events during this interval including a few large filament disappearances on
May 08 from the south-central portion of the disk, one of which was associated with a partial-halo
CME; and a long-duration C8/2N flare at 10/1941UT with associated Type II and IV radio sweeps
from Region 8990 (N14, L = 062, class/area Eki/360 on 13 May). Activity increased to moderate
levels during 12 - 14 May due to isolated low-level M-class flares (see the Energetic Event Summary
for flare times). A 33-degree filament disappeared from the northeast quadrant on 13 May. There were
two large, moderately-complex sunspot groups present on the disk at the end of the period including
Region 8996 (S21, L = 343, class/area Eki/1210 on 13 May) and Region 9002 (N18, L = 304,
class/area Ehi/940 on 15 May).

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SWO PRF 1290 23 May 2000
1
Space Weather Highlights SWO PRF 1290
15 - 21 May 2000 23 May 2000
Solar activity ranged from low to moderate levels with a single period of high activity on 15 May. This
high activity level was due to six M-class events that occurred within a 24-hour period on 15 May (see
the Energetic Event Summary for flare times). Regions 8993 (S21, L = 086, class/area Eao/240 on 15
May), 8998 (S14, L = 333, class/area Fki/470 on 15 May), and 9002 (N18, L = 304, class/area
Ehi/940 on 15 May) all produced M-class events on 15 May. Activity was moderate on 16, 18, and 19
May with a single M-class event occurring on each day. Activity was low on 17, 20, and 21 May,
although an interesting event occurred on 20 May, a C7/1N, with an accompanying Type II and IV
sweep at 20/0535UT from Region 8998. The largest region during the period was 8996 (S21, L = 345,
class/area Ekc/1280 on 16 May). Even though this region maintained a Beta-Gamma magnetic
classification during most of the period, it produced comparatively little activity.

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SWO PRF 1291 29 May 2000
1
Space Weather Highlights SWO PRF 1291
22 - 28 May 2000 29 May 2000
Solar activity was at low to moderate levels. Low activity prevailed most of the period, but rose to
moderate levels on 24 May due to an M1/SF flare at 24/0546UT from Region 8996 (S21, L = 345,
class/area Ekc/1280 on 15 May) and an optically uncorrelated M1 at 24/1152UT. Region 8996 was
gradually decaying at the time of the flare. Occasional C-class subflares occurred during the rest of the
period.

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SWO PRF 1292 06 June 2000
1
Space Weather Highlights SWO PRF 1292
29 May - 04 June 2000 06 June 2000
Solar activity ranged from low to high levels. Activity was at low levels during 29 - 31 May with
isolated C-class flares. Activity increased to moderate levels on 01 June due to an M2/1F flare at
01/0617UT with an associated 420 SFU Tenflare from Region 9026 (N20, L = 074, class/area
Eko/910 on 03 June), which rotated into view on 01 June as a large, moderately complex sunspot
group. This region gradually grew in size and complexity as the period progressed. Activity rose to
high levels during 02 - 03 June due to a pair of major flares from Region 9026 including an M7/2B
parallel-ribbon flare at 02/19138UT and an M6/2B at 03/1924UT with an associated 310 SFU
Tenflare. Region 9026 also produced isolated M-class flares during this time including an M4/1N at
02/0659UT and an M2/1B at 03/0849UT. Activity dropped to moderate levels on 04 June with an
optically uncorrelated M3 flare at 04/2210UT. Note: at the time of this writing Region 9026 had
produced additional major flare activity, which will be discussed in next week's issue.

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SWO PRF 1292 06 June 2000
1
Space Weather Highlights SWO PRF 1293
05 - 11 June 2000 13 June 2000
Solar activity ranged from low to high levels. The period began with activity at moderate levels due to an M1/1F
flare from Region 9031 (S32, L = 150, class/area Cso/110 on 06 June). Activity increased to high levels during
06 - 07 June due to major flare activity from Region 9026 (N21, L = 074, class/area Eko/910 on 03 June). Major
flare activity during this period included an X1/2N at 06/1339UT with an associated 560 SFU Tenflare, an M7
at 06/1401UT; an X2/3B at 06/1525UT with associated Type II and IV radio sweeps, a 2300 SFU Tenflare, 11-degree
DSF, loop-prominence system, full-halo CME, and a solar proton event (see the description below); and a
X1/3B at 07/1553UT with associated Type II and IV radio sweeps, a 200 SFU Tenflare, and a faint full-halo
CME. Region 9026 showed minor changes prior to and during the major activity and was a large, magnetically
complex with a strong magnetic delta structure reported within its leader spot. Region 9026 began a decay phase
on 08 June, which continued through the rest of the period. Region 9031 produced an M2/1B flare at
07/0444UT. Activity decreased to low levels during 08 - 09 June with occasional C-class subflares from Region
9026, which showed significant decay. Region 9033 (N22, L = 016, class/area Fkc/560 on 10 June) showed
significant growth during this period, but produced no flares. Activity increased to high levels on 10 June due to
an M5/3B flare at 10/1702UT from Region 9026 with an associated Type II radio sweep, 550 SFU Tenflare,
loop-prominence system, full-halo CME, and a solar proton event. Activity decreased to moderate levels on the
final day of the period as Region 9033 produced an M1/1F flare at 11/1049UT.

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SWO PRF 1294 20 June 2000
1
Space Weather Highlights SWO PRF 1294
12 - 18 June 2000 20 June 2000
Solar activity ranged from low to high levels. Activity was at low levels during 12 - 14 June due to occasional C-class
subflares. Activity increased to moderate levels on 15 June due to an M1/2N flare at 15/1957UT with an
associated 250 SFU Tenflare and Type II radio sweep from Region 9041 (N18, L = 028, class/area Dao/150 on
12 June) and an M2/1F at 15/2343UT from Region 9040 (N18, L = 303, class/area Cao/100 on 14 June). Solar
activity declined to low levels on 16 June. Activity returned to moderate levels on 17 June as Region 9033 (N23,
L = 016, class/area Fkc/560 on 10 June) produced an M3/2B flare at 17/0237UT. Activity increased to high
levels on 18 June as Region 9033 produced an X1/SF flare at 18/0159UT with an associated 300 SFU Tenflare
and a Type II radio sweep. Region 9033, a moderate-sized mixed-polarity region, had been in a state of gradual
decay prior to the X-flare. This flare occurred as Region 9033 was crossing the west limb.

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SWO PRF 1295 27 June 2000
1
Space Weather Highlights SWO PRF 1295
19 - 25 June 2000 27 June 2000
Solar activity ranged from low to moderate levels. Activity was at low levels during 19 - 20 June due
to occasional C-class subflares. Activity increased to moderate levels on 21 June due to an M1/SF flare
at 21/0929UT from Region 9042 (N24, L = 282, class/area Fko/420 on 21 June). Solar activity
declined to low levels on 22 June. Activity returned to moderate levels on 23 June as Region 9046
(N20, L = 252, class/area Eko/310 on 23 June) produced an M2/2B flare at 23/0407UT with an
associated 240 SFU Tenflare and Type II and IV radio sweeps. Region 9042 produced an M3/1F flare
at 23/1431UT with an associated 250 SFU Tenflare, Type II and IV radio sweeps, and a partial-halo
CME. Solar activity declined to low levels on 24 June. Activity increased to moderate levels on 25
June due to a pair of M-class flares. The first was an M2/SF at 25/0114UT with an associated loop
prominence system from Region 9042, at that time, a day beyond the west limb. The second was an
M1/2N at 25/0752UT from Region 9046. This region showed slow decay during the second half of the
period, and was a small, mixed-polarity spot group at the end of the period.

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SWO PRF 1296 04 July 2000
1
Space Weather Highlights SWO PRF 1296
26 June - 02 July 2000 04 July 2000
Solar activity ranged from low to moderate levels. Activity was low during 26 - 30 June due to isolated
to occasional subflares from a variety of regions. Events of interest during this period included an
optically uncorrelated Type II radio sweep at 26/0144UT and a C3 x-ray flare at 28/1910UT with an
associated eruptive prominence and a Type II radio sweep from Region 9051 (N16, L = 236, class/area
Bxo/010 on 22 June). Activity increased to moderate levels on 01 July due to an optically uncorrelated
M1 x-ray flare at 01/2325UT. Activity decreased to low levels on the final day of the period due to
isolated C-class subflares. Region 9070 (N19, L = 027, class/area Hax/030 on 02 July) produced a
subflare at 02/1541UT with an associated Type II radio sweep.

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SWO PRF 1297 11 July 2000
1
Space Weather Highlights SWO PRF 1297
03 - 09 July 2000 11 July 2000
Solar activity ranged from very low to high levels. Activity was low during 03 - 06 July due to isolated to
occasional C-class subflares from a variety of regions. Events of interest during this period included a 13-degree
filament disappearance from Region 9068 (S18, L = 048, class/area Ekc/390 on 08 July) with an
associated Type II radio sweep at 04/2243UT and a C4/SF at 06/1236UT with an associated Type II radio
sweep from Region 9070 (N18, L = 029, class/area Eac/340 on 08 July). Activity increased to moderate
levels on 07 July due to a pair of M-class flares from Region 9071 (N22, L = 083, class/area Cro/050 on 07
July). The first was an M1/SN at 07/1105UT with an associated Type II radio sweep. The second flare was
an M1/1B at 07/1819UT. Optically uncorrelated Type II radio sweeps occurred at 07/0318UT and
07/2055UT. Images from the SOHO/LASCO instrument showed a halo-type coronal mass ejection (CME)
beginning at 07/1026UT, which may have been associated with a filament disappearance near center disk.
Activity decreased to low levels on 08 July. Activity increased to high levels on 09 July due to an M5/1N
flare at 09/0723UT from Region 9077 (N18, L = 311, class/area Fki/750 on 09 July). Region 9077 rotated
into view on 07 July as a large, magnetically complex sunspot group. Note: at issue time Region 9077 had
produced additional major flares. Details will be provided in next week's issue.

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SWO PRF 1298 18 July 2000
1
Space Weather Highlights SWO PRF 1298
10 - 16 July 2000 18 July 2000
Solar activity was high for most of the period. Region 9077 (N18, L = 310, class/area Fkc/1010 on 11
July), a large group with a magnetically complex (beta-gamma-delta) structure, produced four major
flares during the period. The first of these was a M5/2B long-duration flare at 10/2142UT with
associated Type II and IV radio sweeps that occurred as the region grew at a rapid rate. Region 9077
produced an X1/2N flare at 11/1310UT as the region continued rapid development. This flare was
associated with a 1600 SFU Tenflare and a full-halo coronal mass ejection (CME). Region 9077 also
produced an M4 x-ray flare at 11/1141UT. Region 9070 (N19, L = 029, class/area Fko/680 on 12
July), a large magnetically complex group showed growth as it produced an M1/1N flare at
11/1858UT. Region 9077 produced an X1/2B flare at 12/1037UT accompanied by a 390 SFU
Tenflare and a Type IV radio sweep. Region 9070 added to the major flare count with an M5/2F at
12/1849UT with an associated 230 SFU Tenflare. It also produced a subflare at 12/2013UT with an
associated Type II radio sweep. Solar activity remained high on 13 July due to five low-level M-class
flares from a number of regions including 9070, 9077, and 9085 (N14, L = 254, class/area Eki/270 on
16 July). Region 9077 produced the fourth and largest of its major flares with an X5/3B at 14/1024UT
with an associated 2600 SFU Tenflare, Type II and IV radio sweeps (Type IV duration about 6.5
hours), and a fast-moving halo-CME. This flare also produced a huge solar proton event (see the
description below). Activity decreased to moderate levels on 15 July as Region 9077 began to slowly
decay although it remained large and retained its beta-gamma-delta magnetic structure. Activity
returned to high levels on 16 July with an M5/1N flare at 16/0203UT from Region 9090 (N16, L =
204, class/area Dso/090 on 16 July), as well as an M1/1N flare at 16/2157UT. As the period ended,
Region 9077 continued to gradually decay, but remained large and complex.

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SWO PRF 1299 25 July 2000
1
Space Weather Highlights SWO PRF 1299
17 - 23 July 2000 25 July 2000
Solar activity was at moderate to high levels. The period began with activity at moderate levels as Region 9087
(S12, L = 235, class/area Fkc/790 on 21 July) produced two M-class flares including an M1/1F at 17/1345UT
and an M2/1N at 17/2027UT. Region 9077 (N18, L = 310, class/area Fkc/1010 on 11 July), which was
responsible for last week's X5/3B proton flare, produced an M1/2F flare at 17/0004UT as it slowly decayed.
Activity continued at moderate levels during 18 July with two M-class flares from Region 9077: an M1/2B at
18/0515UT and an M3/SF at 18/1945UT. Region 9087 produced an M3/2N flare at 18/1419UT. Activity
increased to high levels on 19 July due to an M6/3N flare at 19/0726UT from Region 9087. This large,
magnetically complex (beta-gamma-delta structure) region was gradually developing at the time of the flare.
Region 9087 also produced an M5/1B at 20/2025UT as well as an M3/1F at 20/1006UT. A Type II radio sweep
was observed at 20/1652UT and was likely associated with a C5/SF flare from Region 9090 (N12, L = 203,
class/area Fki/340 on 22 July). Activity remained at high levels on 21 July due to an M5/2B from Region 9090 at
21/1437UT. This flare occurred as the region showed an increase in size and complexity. Region 9087, a large
magnetically complex (beta-gamma-delta) group, continued to evolve and produced an M1/SF at 21/1050UT.
Region 9088 (N22, L = 269, class/area Dao/180 on 20 July) produced an M3/SF at 22/0001UT. Activity
decreased to moderate levels on 22 July due to an M3/2N flare at 22/1134UT from Region 9085. This flare was
associated with a proton event at geosynchronous orbit (see the discussion below). Region 9090 produced an
M1/1F flare at 22/0711UT as it showed signs of simplification. Activity remained at moderate levels on the last
day of the period due to M-class flares from Region 9087 including an M1/1N at 23/1000UT and an M1/1N at
23/1413UT.

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SWO PRF 1300 02 August 2000
1
Space Weather Highlights SWO PRF 1300
24 - 30 July 2000 1 August 2000
Solar activity was at low to high levels. The period began with activity at low levels on 24 July.
Activity increased to high levels on 25 July as Region 9097 (N08, L = 170, class/area Ekc/510 on 25
July) produced an M8/2B at 25/0249UT with accompanying Type II and IV radio sweeps. An
associated faint halo CME was observed by LASCO, beginning at 25/0300UT. This region also
produced an M1/1B at 25/1846UT. Region 9087 (S12, L = 235, class/area Fac/380 on 25 July),
produced an M3/2N flare at 25/0456UT as it approached the west limb. Activity dropped to moderate
levels during 26 July, due to a single optically uncorrelated M1 event, with the most likely source being
Region 9087 behind the west limb (S11W94). Activity continued to be moderate on 27 and 28 July
due to minor M-class flares from Region 9090 (N14, L = 203, class/area Fai/380 on 27 July). Activity
decreased to low levels for the last two days of the period.

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SWO PRF 1301 08 August 2000
1
Space Weather Highlights SWO PRF 1301
31 July - 06 Aug 2000 08 August 2000
Solar activity was at low levels throughout the period. Isolated B- and C-class subflares occurred.
Most regions were small and simply-structured. However, Region 9114 (N12, L = 329, class/area
Eao/250 on 06 August) was of moderate size and magnetic complexity and showed gradual growth
during the latter half of the period. Old Region 9077 (N18, L = 310), which produced a number of
major flares during its previous transit, returned as a small, simply-structured sunspot group.

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SWO PRF 1302 15 August 2000
1
Space Weather Highlights SWO PRF 1302
07 - 13 Aug 2000 15 August 2000
Solar activity was at low to moderate levels. Several sunspot groups produced isolated to occasional
C-class subflares during most days. Activity increased to moderate levels on 08 and 12 August by
virtue of isolated, optically uncorrelated M1 X-ray flares at 08/1115UT and 12/0956UT.
SOHO/LASCO images showed a halo CME at around 09/1630UT associated with flare activity from
Region 9114 (N11, L = 330, class/area Eki/340 on 11 August). This CME was the likely source for
severe geomagnetic storm conditions observed on 11 - 12 August (see the discussion below).

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SWO PRF 1303 22 August 2000
1
Space Weather Highlights SWO PRF 1303
14 - 20 August 2000 22 August 2000
Solar activity was low. Isolated C-class flares occurred during the period. By and large, sunspot
groups were small and simply-structured. One exception was Region 9125 (N25, L = 235, class/area
Dai/320 on 15 August), which was of moderate size and magnetic complexity. This region was in a
state of gradual decay as the period ended.
ACE SWEPAM data were not available during 16/1800 - 18/2000UTC and IMF data were not
available during 17/0200 - 2200UTC due to a station-keeping maneuver. A transient passed the
spacecraft early on 15 August accompanied by a velocity increase (490 to 610 km/sec) and increased
densities. IMF Bz was north during most of the period.

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SWO PRF 1304 29 August 2000
1
Space Weather Highlights SWO PRF 1304
21 - 27 August 2000 29 August 2000
Solar activity was at low to moderate levels. Isolated to occasional C-class subflares occurred during
much of the period from a number of mostly small, simply-structured sunspot groups. Activity
increased to moderate levels on 25 August due to an isolated M1/1N flare at 25/1435UTC with
associated Type II and IV radio sweeps from Region 9143 (S19, L = 046, class/area Eao/290 on 27
August), which had just rotated into view at the time of the flare. Region 9143 also produced a long-duration
C1/SF flare at 25/0746UTC with an associated Type II radio sweep. This region was growing
at a moderate pace at the end of the period.

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SWO PRF 1305 05 September 2000
1
Space Weather Highlights SWO PRF 1305
28 August - 03 September 2000 06 September 2000
Solar activity was at low levels during the period. Isolated to occasional C-class subflares occurred
during much of the period from a number of mostly small, simply-structured sunspot groups. The
largest event was a C9/1N at 01/1820 UTC from Region 9140 (N11, L = 079, class/area Dao/130 on
01 September). Region 9149 (N14, L = 356, class/area Eai/240 on 03 September) was the largest
region on the disk at the end of the period. However, this region has shown no significant changes and
has produced only isolated C-class subflares. Region 9154 (S21, L = 328, class/area Bxo/020 on 03
September) was in a growth phase at the end of the period and produced C-class subflares. The
remaining regions were mostly small and stable at the end of the period.
Data were available from the Advanced Composition Explorer (ACE) spacecraft for most of the
period. Velocity was moderately high and density was low for most of the period. These conditions
were consistent with the high-speed coronal hole stream that was the dominant solar wind event during
the period.
There were no proton events detected at geosynchronous orbit during the period.
The greater than 2 MeV electron flux at geosynchronous orbit was at high levels (greater than 1000
pfu) during the period 30 August to 02 September. The greater than 2 MeV electron flux was at
normal levels for the rest of the period.
The geomagnetic field was at quiet or unsettled to active levels during most of the period. Major storm
conditions occurred on 29 August and a brief period of minor storming occurred on 02 September.
These conditions were caused by a high-speed, positive-polarity, coronal hole stream. Geomagnetic
activity declined to quiet to unsettled on the last day of the period.
Space Weather Outlook
06 September - 02 October
Solar activity is expected to be at low to moderate levels. Isolated M-class flares will be possible
sometime during the period.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at moderate to high
levels during 07 September - 09 September. Otherwise, normal to moderate levels are expected.
Geomagnetic field activity is expected to be at unsettled to minor storm levels, with possible major
storming during 07 - 08 September due to a 32-degree filament eruption (last seen near N13 W38) on
04/0500 - 0600 UTC. Quiet to unsettled levels are expected during the remainder of the period, barring
an Earth-directed CME.

***

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NOTE!
There is a possibility that Solar Maximum Cycle 23
occurred July or August 2000
(peak Smoothed 24wk CV: 10th August 2000)

CV-095	BIRGER ANDRESEN	NORWAY	25.jun.00
CV-096	RICHARD GOSSETT	UNITED STATES	29.jun.00
CV-097	JEFFREY MCCAMMON	UNITED STATES	08.jul.00
CV-098	LARRY NANCE	UNITED STATES	19.jul.00
CV-099	FREDRICK VEIO	UNITED STATES	12.aug.00