GEOMETRIC FACTOR IN SEASONAL VARIATIONS OF DAILY AVERAGE VALUES OF THE GEOMAGNETIC INDEX Dₛₜ
Journal Title: Solar-Terrestrial Physics - Year 2020, Vol 6, Issue 4
Abstract
The work uses data on the geomagnetic index Dst for the period 1966–2015. Under quiet conditions, the occurrence of seasonal variations of the daily average Dst index depends on geometric factors of the interaction between the solar wind and the magnetosphere; and under disturbed conditions, on the development of a partial ring current in the magnetosphere. At large negative values of the Dst index, there is no seasonal variation in it. The imperfection of the network of Dst stations is assumed to lead to the formation of annual variation in Dst. The formation of a semiannual variation is associated with the movement of the plasma sheet relative to the plane of the geomagnetic equator during the annual rotation of Earth around the Sun. Based on the data on semiannual variations in the number of days n(Dst), the critical daily average value of the geomagnetic index Dst is determined, starting from which we can speak of disturbed days: Dst≤–24 nT.
Authors and Affiliations
Makarov G. A.
HEURISTIC MODEL OF SOLAR X-RAY SPECTRUM ACCORDING TO SATELLITE DATA FOR GEOPHYSICAL APPLICATIONS
Model and computational algorithm for recovering the X-ray component of the solar spectrum based on GOES XL (0.1–0.8 nm), XS (0.05–0.4 nm or 0.05–0.3 nm) and SDO QD (0.1–7 nm) channels data are presented. The model based...
GALACTIC COSMIC RAY ANISOTROPY MODELLING
We calculate the angular distribution of cosmic rays at a given point of the heliosphere under the assumption that the incoming flux from outer space is isotropic. The static magnetic field is shown to cause no anisotrop...
MESOSTRATOSPHERIC LIDAR FOR THE HELIOGEOPHYSICAL COMPLEX
The Heliogeophysical Complex of RAS, which is developing at the Institute of Solar-Terrestrial Physics SB RAS in the Irkutsk region, includes instruments for studying the Sun, the upper atmosphere and the mesostratospher...
THE PROCESSES OF ENERGY RELEASE IN LOW-POWER SOLAR FLARES
Using flare patrol data for 1972–2010 [http://www.ngdc.noaa.gov/stp/space-weather/solar-data/solar-features/solar-flares/], we have conducted statistical studies of small solar flares. We have established a correlation b...
CHROMOSPHERIC K CAII TELESCOPE OF BAIKAL ASTROPHYSICAL OBSERVATORY. NEW LIGHT
In recent years, most results of CaII studies of the solar chromosphere in H and K lines have been based on observations with narrow passband filters. The Baikal Observatory’s full-disk chromospheric telescope for the K...