Magnetic Storm of January 10-11, 1997

After some period of quiet Sun the exciting Sun-Earth connections event as the big magnetic storm was observed at January 10-11, 1997 by various satellites and ground-based instruments.

Scientist meet this challenge with unprecedented activity and a few data bases was created in relation with solar event/magnetic storm on a few WEB-sites. From the first moment was evident that this magnetic storm happened due to corona mass ejection (CME) from the Sun which form the magnetic cloud in solar wind. This cloud later on interact with the Earth. The terrestrial magnetic field variations display many details how to outer space processes take place.

As a result, a number of analyses are underway on the various aspects of this event. The "hands-on" workshops with on-line access are to focus on the event data. In support of international activity we are pleased to set a home page with geomagnetic data from two points of observations in Russia: Moscow magnetic observatory (lat. 55.5 N, long. 37.3 E) and temporal station in Cape Kamennyi (lat. 68.5 N, long. 73.6 E).

From the presented data we can infer key details of magnetic storm. According the Moscow observatory data the sudden storm commencement (SSC) take place at 01:08 Universal Time of January 10, 1997. The pulse of SSC have positive sign, the duration is around 10 minutes. After moment of SSC as the shock front of magnetic cloud in solar wind hit on the magnetosphere we observe the variations due to currents on the surface of magnetosphere till 05:16 UT. The currents inside the magnetosphere was developed after that with pronounce pick around 07:33 - 07:57 UT of January 10, 1997. Such currents we call "ring currents", there are placed on the distance 3-5 Re around globe and its development presented by Dst index. The deviation in Moscow due to such currents exceed 100 nt. The recovery phase of the magnetic storm take period of next two days with obvious daily variation on Moscow observatory.

The most remarkable disturbance take place in high latitudes. On Cape Kamennyi station we see SSC at 01:08 UT also and prolonged period of strong disturbances at 07:30 - 21:35 UT of January 10, 1997. This period we suppose might be cut off on 4-5 separate bursts of activity according to the H-component.

(Warning ! In Z-component on Cape Kamennyi station we have the strong artificial noise).

Beside the original magnetogrammes we add here the dynamic spectra of magnetic variations based on 1-min. values. The spectra on both observatories are display remarkable similarities. The two periods of intensive fluctuations are exist: first at 11-12 UT, second at 19-21 UT. In each period we have pronounced peaks in spectra which placed in separate bands as follows: 12-18 minutes, 26-30 minutes, 44-48 minutes and 54-58 minutes.

This materials was prepared in the Polar Geophysics Research Sector.

The Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation,
Russian Academy of Sciences,
Troitsk, Moscow region, 142092, RUSSIA