scholarly journals Investigating tensor anisotropy of cosmic rays during large-scale solar wind disturbances

2017 ◽  
Vol 3 (2) ◽  
pp. 22-26
Author(s):  
Петр Гололобов ◽  
Peter Gololobov ◽  
Прокопий Кривошапкин ◽  
Prokopy Krivoshapkin ◽  
Гермоген Крымский ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Cosmic Rays ◽  
Interplanetary Magnetic Field ◽  
Large Scale ◽  
Solar Wind Speed ◽  
Forbush Decrease ◽  
Recovery Phase ◽  
Zonal Harmonic ◽  
Solar Wind Disturbances

The observable anisotropy of cosmic rays has first been decomposed into zonal harmonics and components of vector and tensor anisotropy. We examine Forbush decreases in cosmic rays that occurred in November 2001 and November 2004. It is shown that at the beginning of a Forbush decrease an antisunward convective current of cosmic rays predominates; and during the recovery phase, a sunward diffusive current of particles along the interplanetary magnetic field dominates. During the phase of intensity drop, short-time decreases in the second zonal harmonic take place. These decreases occur with abrupt changes of the interplanetary magnetic field intensity and solar wind speed. During the passage of large-scale solar wind disturbances, the tensor anisotropy behaves in a complicated way. To explain its behavior, a further detailed investigation is required.

scholarly journals Investigating tensor anisotropy of cosmic rays during large-scale solar wind disturbances

2017 ◽  
Vol 3 (2) ◽  
pp. 20-24 ◽  
Author(s):  
Петр Гололобов ◽  
Peter Gololobov ◽  
Прокопий Кривошапкин ◽  
Prokopy Krivoshapkin ◽  
Гермоген Крымский ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Cosmic Rays ◽  
Interplanetary Magnetic Field ◽  
Large Scale ◽  
Solar Wind Speed ◽  
Forbush Decrease ◽  
Recovery Phase ◽  
Zonal Harmonic ◽  
Solar Wind Disturbances

The observable anisotropy of cosmic rays has first been decomposed into zonal harmonics and components of vector and tensor anisotropy. We examine Forbush decreases in cosmic rays that occurred in November 2001 and November 2004. It is shown that at the beginning of a Forbush decrease an antisunward convective current of cosmic rays predominates; and during the recovery phase, a sunward diffusive current of particles along the interplanetary magnetic field dominates. During the phase of intensity drop, short-time decreases in the second zonal harmonic take place. These decreases occur with abrupt changes of the interplanetary magnetic field intensity and solar wind speed. During the passage of large-scale solar wind disturbances, the tensor anisotropy behaves in a complicated way. To explain its behavior, a further detailed investigation is required.

scholarly journals The relativistic electron response in the outer radiation belt during magnetic storms

2002 ◽  
Vol 20 (7) ◽  
pp. 957-965 ◽  
Author(s):  
R. H. A. Iles ◽  
A. N. Fazakerley ◽  
A. D. Johnstone ◽  
N. P. Meredith ◽  
P. Bühler
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Wind Speed ◽  
Interplanetary Magnetic Field ◽  
Relativistic Electron ◽  
Radiation Belt ◽  
Solar Wind Speed ◽  
Recovery Phase ◽  
Magnetic Storms ◽  
Outer Radiation Belt

Abstract. The relativistic electron response in the outer radiation belt during magnetic storms has been studied in relation to solar wind and geomagnetic parameters during the first six months of 1995, a period in which there were a number of recurrent fast solar wind streams. The relativistic electron population was measured by instruments on board the two microsatellites, STRV-1a and STRV-1b, which traversed the radiation belt four times per day from L ~ 1 out to L ~ 7 on highly elliptical, near-equatorial orbits. Variations in the E > 750 keV and E > 1 MeV electrons during the main phase and recovery phase of 17 magnetic storms have been compared with the solar wind speed, interplanetary magnetic field z-component, Bz , the solar wind dynamic pressure and Dst *. Three different types of electron responses are identified, with outcomes that strongly depend on the solar wind speed and interplanetary magnetic field orientation during the magnetic storm recovery phase. Observations also confirm that the L-shell, at which the peak enhancement in the electron count rate occurs has a dependence on Dst *.Key words. Magnetospheric physics (energetic particles, trapped; storms and substorms) – Space plasma physics (charged particle motion and accelerations)

H-Cmes and Ii-Type Radio Bursts Related Intense Geomagnetic Storms in Relation With Interplanetary Magnetic Field and Solar Wind Disturbances

2012 ◽  
Vol 2 (10) ◽  
pp. 1-3 ◽  
Author(s):  
Praveen Kumar Gupta ◽  
◽  
Puspraj Singh Puspraj Singh ◽  
Puspraj Singh Puspraj Singh ◽  
P. K. Chamadia P. K. Chamadia
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Interplanetary Magnetic Field ◽  
Geomagnetic Storms ◽  
Radio Bursts ◽  
Solar Wind Disturbances

scholarly journals The influence of the interplanetary medium on SuperDARN radar scattering occurrence

2000 ◽  
Vol 18 (12) ◽  
pp. 1576-1583 ◽  
Author(s):  
P. Ballatore ◽  
J. P. Villain ◽  
N. Vilmer ◽  
M. Pick
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Interplanetary Magnetic Field ◽  
Interplanetary Medium ◽  
Solar Wind Speed ◽  
Auroral Oval ◽  
Small Degree ◽  
Radio Science ◽  
Ionospheric Physics ◽  
Radar Scattering

Abstract. The effects of the characteristics of the interplanetary medium on the radar scattering occurrence, related to the whole array of SuperDARN radars installed in the Northern Hemisphere, have been studied over a two-year period. Statistically significant correlations of the variation of the scattering occurrence are found with the merging electric field and with the negative Bz component of the interplanetary magnetic field, independent of the seasonal period considered. This result demonstrates that the merging rate (and in particular the reconnection process) between the interplanetary magnetic field and the magnetosphere is a relevant factor affecting the occurrence of scattering. For comparison, we note that no statistically significant correlations are obtained when the interplanetary ion density or the solar wind speed are considered, although also these variables affect to a small degree the scattering occurrence variation. The study of the latitudinal and magnetic local time dependence of the observations shows an association between the considered correlation and the location of the auroral oval and the cusp/cleft region.Key words: Ionosphere (ionospheric irregularities) · Magnetospheric physics (solar wind-magnetosphere interactions) · Radio science (ionospheric physics)

scholarly journals Effect of large-scale inhomogeneity of solar wind velocity on distribution of directions of interplanetary magnetic field vector

2019 ◽  
Vol 5 (3) ◽  
pp. 50-63
Author(s):  
Дмитрий Ерофеев ◽  
Dmitry Erofeev
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Angular Distribution ◽  
Solar Cycle ◽  
Interplanetary Magnetic Field ◽  
Wind Velocity ◽  
High Speed ◽  
Large Scale ◽  
Solar Wind Velocity ◽  
Statistical Characteristics

Using data with hourly resolution obtained in near-Earth heliosphere in 1965–2014, we have calculated statistical characteristics of the angles describing the direction of the interplanetary magnetic field (IMF): root-mean-square deviations of azimuthal and elevation angles, asymmetries of their distributions, and coefficient of correlation of the angles. It has been shown that the above characteristics varied in the course of solar cycle, and some of them changed their signs when solar polar magnetic field reversed. The results obtained from the experimental data analysis were compared with a model describing transport of large-scale disturbances of IMF lines by the inhomogeneous solar wind. The comparison has shown that the variations in the angular distribution of IMF in the course of solar cycle probably occur due to the appearance of the large-scale latitudinal gradient of solar wind velocity during solar minima. In addition, the angular distribution of IMF has been found to be substantially affected by the longitudinal velocity gradient in trailing parts of high-speed streams and short-term local-scale variations in velocity gradients.

scholarly journals PENGARUH ORIENTASI MEDAN MAGNET ANTARPLANET PADA GANGGUAN GEOMAGNET DI LINTANG RENDAH

2016 ◽  
Vol 13 (2) ◽  
pp. 73
Author(s):  
Anton Winarko ◽  
Anwar Santoso
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Interplanetary Magnetic Field ◽  
Geomagnetic Storm ◽  
Interplanetary Space ◽  
Recovery Phase ◽  
Geomagnetic Disturbance ◽  
Wind Condition ◽  
Low Latitude ◽  
Sudden Impulse

Interplanetary Magnetic Field (IMF) is a part of the Solar magnetic field that is carried into interplanetary space by the solar wind. Based on previous study it is known that solar wind condition when reconnection occurs has important role on geomagnetic disturbance. This paper discusses low-latitude geomagnetic field responses to various condition of reconnection, i.e. when north-south component of Interplanetary Magnetic Field (IMF Bz) was south-directed (<0) in long duration, IMF Bz switch to opposite direction after reconnection, and neutral IMF Bz (~0). Case studies show that precondition which IMF Bz<0 prompt more intense geomagnetic storm compared to IMF Bz ~0. At low latitude, precondition of IMF Bz <0 tend to trigger disturbance in the form of geomagnetic storm, while the IMF Bz~0 one could trigger Sudden Impulse. Change of IMF Bz direction after reconnection affected recovery phase acceleration, that was on IMF Bz>0, recovery phase  took less time compared to IMF Bz<0. AbstrakMedan magnet antarplanet (Interplanetary Magnetic Field/IMF) adalah medan magnet matahari yang dibawa oleh angin surya dan menjalar dalam ruang antarplanet. Berdasarkan studi sebelumnya diketahui bahwa kondisi angin surya saat terjadi rekoneksi amat berpengaruh terhadap gangguan geomagnet yang terjadi. Pada makalah ini dibahas respons medan geomagnet di lintang rendah pada berbagai kondisi rekoneksi yaitu pada saat komponen utara-selatan medan magnet antarplanet (IMF Bz) dominan selatan (IMF Bz<0) dalam durasi panjang, IMF Bz berbalik arah setelah rekoneksi, dan  IMF Bz cenderung netral (IMF Bz~0). Dari studi kasus menunjukkan bahwa prakondisi IMF Bz <0 mengakibatkan badai geomagnet yang lebih intens dibandingkan IMF Bz~0. Di lintang rendah, prakondisi IMF Bz<0 cenderung mengakibatkan gangguan berupa badai geomagnet sedangkan IMF Bz~0 dapat memicu Sudden Impulse. Perubahan arah IMF Bz yang terjadi setelah rekoneksi mempengaruhi laju fase pemulihan (recovery phase), yaitu pada IMF Bz>0, fase pemulihannya cenderung berlangsung lebih cepat dibandingkan saat IMF Bz<0.

Sign in / Sign up

Export Citation Format

Share Document