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HELIOS no. 50        01.March 1998

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.  This is the reason why this issue has the number 50!  This Helios Newsletter is supposed to be issued on a bi-monthly basis and I hope you will enjoy reading the latest solar news.
Comments?   Post them!

Solar Cycle #23 started 25June96 (comparison between CV, CV made from USAF-region Reports and 10,7cm Solar Flux observed at Pentiction, Canada) The rise began very slowly as the groundlevels had persisted from 01Apr96 to 27Aug97 (levels where 24wkSmCV was under 10,0).  Finally, though very dramatic, we saw a rise in the period 04-18Sep97.  The expectations of a beginning cycle were probably great among us all!  The top was marked 09Sep97 with a CV of 145!  The CV-P.Index (acceleration/retardation model: 28-day change 24wkSmCV then 24wkSmP.I.) had a day-maximum on 11-12Sep97 with 6,2% per day, resulting in the smoothed value of 29,7% on 27Jan98.   On the 26Jan98 and 28Jan98 we had a CV-max of 152 and 142 observed by 5 and 3 observers respectively.
See the graph on the Index page.

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Latest solar news as to some details referred from NOAA/SWO of Boulder, Colorado, USA:
(SWO 1170/1171/1172)

Region 8142 (S21, L = 345, class/area Dso/12 on 26 January) produced a C5/SN flare at 26/2235UT with an associated Type II radio sweep and minor discrete centimetric bursts. Another Type II sweep was detected at 27/2214UT, but was not optically correlated. Isolated B- and C-class X-ray bursts occurred during the rest of the period.
The greater than 2 MeV electron flux at geosynchronous altitude briefly reached moderate to high levels during 30 January.
The geomagnetic field was at mostly quiet to unsettled levels through 28 January. Activity increased during 29 - 30 January with active to minor storm levels reported at all latitudes and brief, isolated major storm periods at high latitudes. Activity declined to mostly quiet levels early 31 January, but increased to active levels late in the day. Activity returned to mostly quiet levels on 01 February.
Activity increased late 08February with unsettled to active levels observed at middle latitudes and unsettled to major storm levels observed at high latitudes.
Region 8156 (S24, L = 033, class/area Eki/360 on 15 February) grew steadily and produced occasional B-class subflares during most of the period. The region also produced an isolated C-class subflare at 15/0424UT that was associated with a 190 SFU Tenflare. A 120 SFU Tenflare occurred at 15/0102UT, but was not optically associated.
There were no significant proton enhancements observed at geosynchronous altitude.
The greater than 2 MeV electron flux at geosynchronous altitude was at moderate to high levels during 12 - 15 February.
Region 8156 (S25, L = 033, class/area Eki/520 on 16 February) produced isolated C-class subflares on 17 - 18 February during a period of gradual growth.
The greater than 2 MeV electron flux at geosynchronous altitude was at moderate to high levels during 16 - 17 and 21 February.
The geomagnetic field was at quiet levels through midday, 17 February. A disturbance began during the latter half of 17 February and continued through 18 February. Active to major storm conditions were detected at all latitudes during the disturbance.


Helios no. 51 will be issued 01. May 1998