Geomagnetic substorm activity associated with magnetic clouds

Бархатов, Н. А.; Vinogradov, A. B.; Левитин, А. Е.; Ревунова, Е. А.

doi:10.1134/s0016793215050023

Cited by 3 publications

(2 citation statements)

References 7 publications

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“…Учет изменения ориентации магнитного поля МО относительно плоскости эклиптики в течение года позволяет улучшить качество прогноза интенсивности геомагнитных бурь [Бархатов и др., 2014]. Ударная волна и область турбулентного сжатия плазмы являются основными источниками возникновения геомагнитных возмущений, дальнейшее развитие которых обеспечивается плазмой МО [Barkhatov et al, 2015].…”

Section: рис 6 структура квмunclassified

Fe/O ratio behavior as an indicator of solar plasma state at different solar activity manifestations and in periods of their absence

Minasiants¹,

Minasyants

Minasiants³

et al. 2018

Solnechno-Zemnaya Fizika

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We report the results of the investigation into plasma physical characteristics at various solar activity manifestations and in periods of their absence. These results have been obtained from quantitative estimates of the relative abundance of Fe/O ions in different energy ranges. Maximum values of the Fe/O ratio is shown to correspond to particle fluxes from impulsive flares for ions with energies <2 MeV/n (the most significant manifestation of the FIP effect). In particle fluxes from gradual flares, the Fe/O value decreases smoothly with ion energy and is noticeably inferior to values of fluxes in impulsive events. We have established that the properties of flares of solar cosmic rays indicate their belonging to a separate subclass in the total population of gradual events. Relying on variations in the abundance of Fe/O ions, we propose an xplanation of the solar plasma behavior during the development of flares of both classes. Magnetic clouds (a separate type of coronal mass ejections (CME)), which have regions of turbulent compression and are sources of strong geomagnetic storms, exhibit a relative composition of Fe ions comparable to the abundance of Fe in ion fluxes from gradual flares. We have found out that the Fe/O value can be used to detect penetration of energetic flare plasma into the CME body at the initial phase of their joint development and to estimate its relative contribution. During solar minimum with complete absence of sunspots, the Fe/O ratio during periods of “quiet” solar wind show absolutely low values of Fe/O=0.004–0.010 in the energy range from 2–5 to 30 MeV/n. This is associated with the manifestation of the cosmic ray anomalous component, which causes an increase in the intensity of ion fluxes with a high first ionization potential, including oxygen (O), and elements with a low first ionization potential (Fe) demonstrate weakening of the fluxes. As for particles with higher energies (Ek>30 MeV/n), the Fe/O increase is due to the decisive influence of galactic cosmic rays on the composition of impurity elements in the solar wind under solar minimum conditions. The relative content of heavy elements in galactic cosmic rays 30–500 MeV/n is similar to values in fluxes from gradual flares during high solar activity. During solar minimum without sunspots, the behavior of Fe/O for different ion energy ranges in plasma flows from coronal holes (CH) and in the solar wind exhibits only minor deviations. At the same time, plasma flows associated with the disturbed frontal CH region can be sources of moderate geomagnetic storms.

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Section: рис 6 структура квмunclassified

Fe/O ratio behavior as an indicator of solar plasma state at different solar activity manifestations and in periods of their absence

Minasiants¹,

Minasyants

Minasiants³

et al. 2018

Solnechno-Zemnaya Fizika

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“…Consideration of a change in the MC magnetic field orientation relative to the plane of the ecliptic within a year makes it possible to improve the accuracy of the forecast of geomagnetic storm intensity [Barkhatov et al, 2014]. Shocks and shells are the main sources of geomagnetic disturbances, the further development of which is provided by MC plasma [Barkhatov et al, 2015].…”

Section: Variations In Fe/o With Ion Energy In Structures Of Magneticmentioning

confidence: 99%

Fe/O ratio behavior as an indicator of solar plasma state at different solar activity manifestations and in periods of their absence

Minasiants¹,

Minasyants

Minasiants³

et al. 2018

Solar-Terrestrial Physics

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Abstract. We report the results of the investigation into plasma physical characteristics at various solar activity manifestations and in periods of their absence. These results have been obtained from quantitative estimates of the relative abundance of Fe and O ions in different energy ranges. Maximum values of the Fe/O ratio is shown to correspond to particle fluxes from impulsive flares for ions with energies <2 MeV/n (the most significant manifestation of the first ionization potential (FIP) effect). In particle fluxes from gradual flares, the Fe/O value decreases smoothly with ion energy and is noticeably inferior to values of fluxes in impulsive events. We have established that the properties of flares of solar cosmic rays indicate their belonging to a separate subclass in the total population of gradual events. Relying on Fe/O variations, we propose an explanation of the solar plasma behavior during the development of flares of both classes.Magnetic clouds (a separate class of coronal mass ejections (CME)), which have turbulent compression regions and are sources of strong geomagnetic storms, exhibit a relative composition of Fe ions comparable to the abundance of Fe in ion fluxes from gradual flares.We have found out that the Fe/O value can be used to detect penetration of energetic flare plasma into the CME body at the initial phase of their joint development and to estimate its relative contribution.During solar minimum with complete absence of sunspots, the Fe/O ratio at a distance of 1 AU show absolutely low values of Fe/O=0.004-0.010 in the energy range from 2-5 to 30 MeV/n. This is associated with the manifestation of the cosmic ray anomalous component, which causes an increase in the intensity of ion fluxes with a high FIP, including oxygen (O), and elements with a low FIP (Fe) demonstrate weakening of the fluxes. As for particles with higher energies (E k >30 MeV/n), the Fe/O increase is due to the decisive influence of galactic cosmic rays on the composition of admixtures in the solar wind under solar minimum conditions. The abundance of heavy elements in galactic cosmic rays 30-500 MeV/n is similar to values in fluxes from gradual flares during high solar activity.During solar minimum without sunspots, the Fe/O behavior for different ion energy ranges in plasma flows from coronal holes (CH) and in the solar wind exhibits only minor deviations. At the same time, plasma flow associated with the disturbed frontal CH region can be sources of moderate geomagnetic storms.

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