Dynamic 10 MK plasma structures observed in monochromatic full-Sun images by the SPIRIT spectroheliograph on the CORONAS-F mission

Abstract

High-resolution temporal series of monochromatic full-Sun images in the L Mg XII emission line at 8.42Å have been obtained by the SPectroheliographIc X-Ray Imaging Telescope (SPIRIT) spectroheliograph on the CORONAS-F satellite. For a six-month period since the launch on 2001 July 31 more than 10 000 Mg XII images were recorded. The images revealed plasma structures with the temperature in the range 3-20 MK characterized by specific shape and dynamics, different to that of relatively low temperature (1-2 MK) plasma. The main remarkable features of the phenomena first seen in the monochromatic images are as follows:(1) high spatial variability in brightness with the contrast of more than two orders of magnitude, (2) the presence of some compact sources with high altitude locations up to 0.3 solar radius and well-distinguished 'spider'-like forms, (3) substantially different variability in dynamical behaviour characterized by lifetimes from minutes to days. Sporadic condensations of coronal plasma with log N e ≈ 10 and peak temperature of about 10 MK were observed in the vicinity of active region systems.

Main Results of the SPIRIT Experiment Onboard the CORONAS-F Satellite

“…These phenomena are manifested as a glowing of bright hot ( T = 5-20 MK) plasma structures high in the solar corona and are characterized by specific shapes and dynamics (Zhitnik et al , 2003a):…”

“…Eruptive events (coronal mass ejections, prominence eruption, etc.) were simultaneously registered for the first time in two wavelengths corresponding to excitation temperatures of 1 MK and 0.08 MK (Zhitnik et al, 2003a(Zhitnik et al, , 2003b. The results of such observations are presented in Fig.…”

Recent Progress and Future Prospects in Solar Physics, and Their Relevance for Planet Earth

“…A description of the mission can be found in Novosti Kosmonavtiki (Space News, No.9, 2001;No.5, 2002, in Russian). The Spectroheliographic X-Ray Telescope (SPIRIT) has recorded images of high-temperature plasma (3-20 MK) in Mg XII and found compact sources at locations up to 0.3 R x from the limb (Zhitnik et al, 2003). A third mission (PHOTON) is foreseen to follow the present one.…”

The Dynamics of High-Temperature Plasma in the Solar Corona according to SPIRIT Observations in Mg XII 8.42 Å Line

“…The SPIRIT instrumentation onboard the CORO-NAS-F satellite is designed to obtain full-disk images of the Sun in soft-X-ray and extreme-UV spectral channels and lines (for a technical description of the SPIRIT instrumentation, see Zhitnik et al , 2003).…”

“…Currently, the spatial and temporal parameters of the high-temperature coronal plasma are studied with the RES-K X-ray spectroheliograph, which is part of the SPIRIT complex operated onboard the CORONAS-F satellite (Oraevskii et al , 2002). The RES-K spectroheliograph provides monochromatic images of the full solar disk in the Mg XII 8.42-Å line with a temperature of T = 5-15 MK (Zhitnik et al , 2003). This makes it possible to directly observe the hot coronal plasma, whereas the data of the Yohkoh satellite can be used to reveal the high-temperature plasma only indirectly, by comparing SXT images obtained with various filters.…”