Variations of geomagnetic thresholds of cosmic rays and magnetospheric parameters during different phases  of the storm of November 20, 2003

2021 ◽  
Author(s):  
Elena Vernova ◽  
Natalia Ptitsyna ◽  
Olga Danilova ◽  
Marta Tyasto
Keyword(s):  
Solar Wind ◽  
Cosmic Rays ◽  
Hysteresis Loop ◽  
Magnetic Storm ◽  
Cosmic Ray ◽  
Recovery Phase ◽  
Main Phase ◽  
Cutoff Rigidity ◽  
The Relationship ◽  
Current Systems

<div> <p>The correlations between variations in the geomagnetic cutoff rigidity of cosmic rays and the Dst and Kp geomagnetic indices and solar-wind and IMF parameters are calculated for the three phases of the magnetic storm of November 20–21, 2003: before the storm and during its main and recovery phases. The correlations are the strongest between variations in the cutoff rigidity and the Dst index during all stages. A significant correlation was recorded with the By component of IMF and the field magnitude B; the correlation with By dominated during the main phase, and the correlation with B was dominant during the recovery phase. There is also a high correlation with the dynamic parameters of solar activity during the main phase, especially with the solar-wind speed.</p> <div> <p>As far as we know, hysteresis phenomena have been discovered for the first time in the relationship between the cosmic-ray cutoff rigidities and the parameters of the helio- and magnetosphere on the scale of the magnetic storm (with Moscow station as an example). Loop-like patterns formed, because the trajectories of variations in the cutoff rigidities versus the studied parameters during storm intensification (development of current systems) did not coincide with the trajectories during the recovery phase (decay of current systems). The correlations of the cutoff rigidities with Dst and Kp indices were characterized by a narrow hysteresis loop, and their correlations with the IMF parameters were characterized by a wide hysteresis loop. The hysteresis loops for the relationship between the cutoff rigidities and solar-wind density and pressure were disordered.</p> </div> </div>

scholarly journals DISTURBED MAGNETOSPHERE ON NOVEMBER 7–8, 2004AND VARIATIONS OF COSMIC RAY CUTOFF RIGIDITY: LATITUDE EFFECTS

2020 ◽  
Vol 6 (3) ◽  
pp. 40-47
Author(s):  
Olga Danilova ◽  
Natalia Ptitsyna ◽  
Marta Tyasto ◽  
Valeriy Sdobnov
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Neutron Monitor ◽  
Cosmic Ray ◽  
Recovery Phase ◽  
Survey Method ◽  
Cutoff Rigidity ◽  
Strong Magnetic Storm ◽  
Current Systems ◽  
Activity Indices

We have studied the latitude behavior of cosmic ray cutoff rigidity and their sensitivity to Bz and By components of the interplanetary magnetic field and geomagnetic activity indices Dst and Kp for different phases of the November 7–8, 2004 strong magnetic storm. Cutoff rigidities have been calculated using two methods: the spectrographic global survey method in which the cutoff rigidity is determined from observational data, acquired by the neutron monitor network, and the method in which particle trajectories are calculated numerically in a model magnetic field of the magnetosphere. We have found that the sensitivity of observed cutoff rigidities to Dst changes with latitude (threshold rigidity of stations) is in antiphase with changes in the sensitivity to By. During the recovery phase of the storm, the Dst correlation with By is significantly greater than that with Bz, and the Kp correlation with Bz is greater than that with By. The By component is shown to be a predominant driver of the current systems that determine the Dst evolution during the recovery phase.

scholarly journals Parameters of current systems in the magnetosphere as derived from observations of cosmic rays during the June 2015 magnetic storm

2017 ◽  
Vol 3 (3) ◽  
pp. 13-17 ◽  
Author(s):  
Геннадий Кичигин ◽  
Gennadiy Kichigin ◽  
Марина Кравцова ◽  
Marina Kravtsova ◽  
Валерий Сдобнов ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Magnetic Storm ◽  
Ring Current ◽  
Planetary System ◽  
Cutoff Rigidity ◽  
Geomagnetic Cutoff Rigidity ◽  
Geomagnetic Cutoff ◽  
Subsolar Point ◽  
Worldwide Network ◽  
Current Systems

Basing on measurements of cosmic rays at the worldwide network of stations, we calculate variations in the planetary system of geomagnetic cutoff rigidity for the 2015 June moderate geomagnetic storm. Using the axisymmetric model of the limited magnetosphere taking into account magnetopause currents and the ring current, we determine the distance to the subsolar point and the ring current radius, as well as the contribution of the ring current to variations in the geomagnetic cutoff rigidity and to the Dst index.

scholarly journals Parameters of current systems in the magnetosphere as derived from observations of cosmic rays during the June 2015 magnetic storm

2017 ◽  
Vol 3 (3) ◽  
pp. 15-19 ◽  
Author(s):  
Геннадий Кичигин ◽  
Gennadiy Kichigin ◽  
Марина Кравцова ◽  
Marina Kravtsova ◽  
Валерий Сдобнов ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Magnetic Storm ◽  
Ring Current ◽  
Planetary System ◽  
Cutoff Rigidity ◽  
Geomagnetic Cutoff Rigidity ◽  
Geomagnetic Cutoff ◽  
Subsolar Point ◽  
Worldwide Network ◽  
Current Systems

Basing on measurements of cosmic rays at the worldwide network of stations, we calculate variations in the planetary system of geomagnetic cutoff rigidity for the 2015 June moderate geomagnetic storm. Using the axisymmetric model of the limited magnetosphere taking into account magnetopause currents and the ring current, we determine the distance to the subsolar point and the ring current radius, as well as the contribution of the ring current to variations in the geomagnetic cutoff rigidity and to the Dst index.

scholarly journals DISTURBED MAGNETOSPHERE ON NOVEMBER 7–8, 2004AND VARIATIONS OF COSMIC RAY CUTOFF RIGIDITY: LATITUDE EFFECTS

2020 ◽  
Vol 6 (3) ◽  
pp. 34-39
Author(s):  
Olga Danilova ◽  
Natalia Ptitsyna ◽  
Marta Tyasto ◽  
Valeriy Sdobnov
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Neutron Monitor ◽  
Cosmic Ray ◽  
Recovery Phase ◽  
Survey Method ◽  
Cutoff Rigidity ◽  
Strong Magnetic Storm ◽  
Current Systems ◽  
Activity Indices

We have studied the latitude behavior of cosmic ray cutoff rigidity and their sensitivity to Bz and By components of the interplanetary magnetic field and geomagnetic activity indices Dst and Kp for different phases of the November 7–8, 2004 strong magnetic storm. Cutoff rigidities have been calculated using two methods: the spectrographic global survey method in which the cutoff rigidity is determined from observational data, acquired by the neutron monitor network, and the method in which particle trajectories are calculated numerically in a model magnetic field of the magnetosphere. We have found that the sensitivity of observed cutoff rigidities to Dst changes with latitude (threshold rigidity of stations) is in antiphase with changes in the sensitivity to By. During the recovery phase of the storm, the Dst correlation with By is significantly greater than that with Bz, and the Kp correlation with Bz is greater than that with By. The By component is shown to be a predominant driver of the current systems that determine the Dst evolution during the recovery phase.

scholarly journals RELATIONSHIP OF THE ASY-H INDEX WITH INTERPLANETARY MEDIUM PARAMETERS AND AURORAL ACTIVITY IN MAGNETIC STORM MAIN PHASES DURING CIR AND ICME EVENTS

2020 ◽  
Vol 6 (1) ◽  
pp. 43-50
Author(s):  
Roman Boroev ◽  
Mikhail Vasiliev
Keyword(s):  
Magnetic Storm ◽  
Interplanetary Medium ◽  
Magnetic Storms ◽  
Main Phase ◽  
Storm Main Phase ◽  
H Index ◽  
Auroral Activity ◽  
Different Types ◽  
Relationship Of ◽  
The Relationship

In this study, we examine the relationship of the ASY-H index characterizing the partial ring current intensity with interplanetary medium parameters and auroral activity during the main phase of magnetic storms, induced by the solar wind (SW) of different types. Over the period 1979–2017, 107 magnetic storms driven by CIR and ICME (MC + Ejecta) events have been selected. We consider magnetic storms with Dstmin≤ – 50 nT. The average ASY-H index (ASYaver) during the magnetic storm main phase is shown to increase with increasing SW electric field and southward IMF Bz regardless of SW type. There is no relationship between ASYaver and SW velocity. For the CIR and ICME events, the average AE (AEaver) and Kp (Kp aver) indices have been found to correlate with ASYaver. The highest correlation coefficient between AEaver and ASYaver (r = 0.74) is observed for the magnetic storms generated by CIR events. A closer relationship between Kp aver and ASYaver (r = 0.64) is observed for the magnetic storms induced by ICME events. The ASYaver variations correlate with Dstmin. The relationship between ASYaver and the rate of storm development is weak.

scholarly journals The ionospheric storm studies: further development of the mapping technique

1996 ◽  
Vol 39 (4) ◽  
Author(s):  
I. Kutiev ◽  
T. Samardjiev ◽  
P. A. Bradley ◽  
M. I. Dick ◽  
L. R. Cander
Keyword(s):  
Magnetic Storm ◽  
Recovery Phase ◽  
Main Phase ◽  
Mapping Technique ◽  
Ionospheric Storm ◽  
Further Development

The technique of using instantaneous maps for ionospheric storm studies is further developed. Integral parameters are introduced characterizing the main features of each map. These parameters are the net volumes of ?f0F2, ?M(3000)F2and their gradients. The magnetic storm 1-2 March, 1982 was considered and it was found that before the storm commencement and in recovery phase the Net Gradient (NG) is directed steadily to the East, while in the main phase it turns southward. NG shows where the changes of the F-layer come from. The net volume of ?f0F2 (NF) correlates well with Dst and AE indices.

Galactic cosmic-ray modulation effect by solar-wind streams

1995 ◽  
Vol 73 (9-10) ◽  
pp. 642-646 ◽  
Author(s):  
M. A. El-Borie
Keyword(s):  
Solar Wind ◽  
Wind Speed ◽  
Cosmic Rays ◽  
Solar Wind Speed ◽  
Cosmic Ray ◽  
Diurnal Variations ◽  
Solar Cycles ◽  
Mean Values ◽  
Wind Speeds ◽  
Cosmic Ray Modulation

Data, from the worldwide network of neutron monitors, recorded at Deep River, Hermanus, Rome, Tokyo, and Huancayo, over two solar cycles (Nos. 20 and 21) are analyzed to study the long-term variations of the solar diurnal variations as they relate to solar-wind speed. The median primary rigidities of response (Rm) for these detectors cover the range 16 GV ≤ Rm ≤ 33 GV. We discuss the solar diurnal variations (amplitude and phase) of cosmic rays as a function of solar activity. The behavior of solar diurnal phases is completely different for the two epochs of high-wind speed. Data of solar-wind speed from 1966–1986 are classified according to the state of the daily mean values. Variation in the amplitudes of the diurnal variations, as functions of the median primary rigidity of cosmic rays, for the two selected periods (1973–1975 and 1979–1981) of high and low solar-wind speeds were determined at the selected stations. The rigidity dependence of the averaged solar diurnal variations of cosmic rays related to the high solar-wind speed was studied. The most sensitive rigidity of modulation is around 20 and 30 GV during the 1973–1975 and 1979–1981 periods, respectively. Our results also show that there is a significant correlation in the solar diurnal amplitudes between the two divisions of high and low solar-wind speed days.

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