AbstractThe paper presents data on ionizing short-wave UV-emission of the Sun in a wave-range λ⩽130nm measured on-board the CORONAS-I and CORONAS-F satellites. There were obtained absolute values of solar flux emission in the spectrum range λ⩽130nm and the band near H Lα hydrogen line on-board both satellites. Measurements on-board the CORONAS-I satellite coincided with a phase near the minimum of solar activity (F10.7=80–100). In the period from March to June of 1994 the solar flux was equal on the average to 7.5ergcm−2s−1 for λ⩽130nm and the intensity of emission in H Lα was equal to (5.5–6.1)ergcm−2s−1. The measurements on-board the CORONAS-F were performed near the maximum of solar activity (F10.7=143–279). Emission intensity in H Lα line was about 6.8 –8.2ergcm−2s−1 and in the wave-range λ⩽130nm it was equal on the average to 11–13ergcm−2s−1. EUV measurements are in agreement with the data obtained on-board UARS satellite and with the results of ionospheric measurement of E-layer critical frequencies. These measurements agree with data of contemporary models as well.A lot of flares including bright ones were observed. The measurement data of a bright flare of X-ray class X5.3 on 25.05.2001 are given. The paper presents the results of comparison between the CORONAS-F data and the X-ray fluxes in waveband 0.1–0.8nm (GOES).This comparison demonstrated that X-ray emission measured on-board the GOES spacecraft and measured due to SUVR instrument (with filters in wave-range <12nm) changed almost synchronously in the ranges 0.1–0.8 and 0.1–12nm. The data measured due to VUSS showed that EUV emission appeared a few minutes (1–13) before X-ray emission. Apparently it evidences that at first a flare begins in the chromosphere and then a heating area is spreading higher. Solar emission increases by ∼20–30% in the range λ<130nm, and only by 8–10% in EUV range. Changes of extreme ultraviolet (EUV) solar flux were registered during the annular solar eclipse of May 31, 2003, when the CORONAS-F satellite thrice intersected a zone of the solar eclipse.


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    Title :

    A flux of EUV emission measured on-board the “CORONAS” artificial satellites near minimum and maximum of the 23rd cycle of solar activity


    Contributors:

    Published in:

    Advances in Space Research ; 37 , 2 ; 246-252


    Publication date :

    2005-03-09


    Size :

    7 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English