Correlation between the variations of cosmic ray geomagnetic thresholds and interplanetary parameters during various phases of solar disturbance in November 2004

2020 ◽  
Author(s):  
Elena Vernova ◽  
Natalia Ptitsyna ◽  
Olga Danilova ◽  
Marta Tyasto
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Fields ◽  
Interplanetary Magnetic Field ◽  
Particle Flux ◽  
Cosmic Ray ◽  
Dynamic Interaction ◽  
Cutoff Rigidity ◽  
Geomagnetic Cutoff Rigidity ◽  
Geomagnetic Cutoff

<p>The geomagnetic cutoff rigidity R (momentum per unit charge) is the threshold rigidity below which the particle flux becomes zero due to geomagnetic shielding. The properties of the geomagnetic screen vary greatly during magnetic storms, depending on the dynamic interaction of the solar wind (SW) magnetic fields with the magnetospheric fields and currents. The correlation between the variations of geomagnetic cutoff rigidity ΔR and interplanetary parameters and geomagnetic activity indexes during various phases of the superstorm on November 7 – 8, 2004 has been calculated. On the scale of the entire storm the most geoeffеctive parameters were Dst, Kp, and SW speed, while other parameters, including total interplanetary magnetic field B and Bz component, were effective at different phases of the storm.</p>

Degenerate induced magnetospheres

2020 ◽  
Author(s):  
Stas Barabash ◽  
Andrii Voshchepynets ◽  
Mats Holmström ◽  
Futaana Yoshifumi ◽  
Robin Ramstad
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Fields ◽  
Interplanetary Magnetic Field ◽  
Solar Wind Plasma ◽  
Stellar Winds ◽  
Ionospheric Currents ◽  
Magnetic Barrier ◽  
Atmospheric Escape ◽  
The Subject

<p>Induced magnetospheres of non-magnetized atmospheric bodies like Mars and Venus are formed by magnetic fields of ionospheric currents induced by the convective electric field E = - V x B/c of the solar wind. The induced magnetic fields create a magnetic barrier which forms a void of the solar wind plasma, an induced magnetosphere. But what happens when the interplanetary magnetic field is mostly radial and the convective field E ≈ 0? Do a magnetic barrier and solar wind void form? If yes, how such a degenerate induced magnetosphere work? The question is directly related to the problem of the atmospheric escape due to the interaction with the solar and stellar winds. The radial interplanetary magnetic field in the inner solar system is typical for the ancient Sun conditions and exoplanets on near-star orbits. Also, the radial interplanetary field may provide stronger coupling of the near-planet environment with the solar/stellar winds and thus effectively channels the solar/stellar wind energy to the ionospheric ions. We review the current works on the subject, show examples of degenerate induced magnetospheres of Mars and Venus from Mars Express, Venus Express, and MAVEN measurements and hybrid simulations, discuss physics of degenerate induced magnetospheres, and impact of such configurations on the escape processes.</p>

scholarly journals Latitudinal variation rate of geomagnetic cutoff rigidity in the active Chilean convergent margin

2018 ◽  
Vol 36 (1) ◽  
pp. 275-285 ◽  
Author(s):  
Enrique G. Cordaro ◽  
Patricio Venegas ◽  
David Laroze
Keyword(s):  
Magnetic Field ◽  
Vertical Component ◽  
Cutoff Rigidity ◽  
Earth’S Magnetic Field ◽  
Convergent Margin ◽  
Flat Slab ◽  
Geomagnetic Cutoff Rigidity ◽  
Geomagnetic Cutoff ◽  
Variation Rate ◽  
Earth's Magnetic Field

Abstract. We present a different view of secular variation of the Earth's magnetic field, through the variations in the threshold rigidity known as the variation rate of geomagnetic cutoff rigidity (VRc). As the geomagnetic cutoff rigidity (Rc) lets us differentiate between charged particle trajectories arriving at the Earth and the Earth's magnetic field, we used the VRc to look for internal variations in the latter, close to the 70° south meridian. Due to the fact that the empirical data of total magnetic field BF and vertical magnetic field Bz obtained at Putre (OP) and Los Cerrillos (OLC) stations are consistent with the displacement of the South Atlantic magnetic anomaly (SAMA), we detected that the VRc does not fully correlate to SAMA in central Chile. Besides, the lower section of VRc seems to correlate perfectly with important geological features, like the flat slab in the active Chilean convergent margin. Based on this, we next focused our attention on the empirical variations of the vertical component of the magnetic field Bz, recorded in OP prior to the Maule earthquake in 2010, which occurred in the middle of the Chilean flat slab. We found a jump in Bz values and main frequencies from 3.510 to 5.860 µHz, in the second derivative of Bz, which corresponds to similar magnetic behavior found by other research groups, but at lower frequency ranges. Then, we extended this analysis to other relevant subduction seismic events, like Sumatra in 2004 and Tohoku in 2011, using data from the Guam station. Similar records and the main frequencies before each event were found. Thus, these results seem to show that magnetic anomalies recorded on different timescales, as VRc (decades) and Bz (days), may correlate with some geological events, as the lithosphere–atmosphere–ionosphere coupling (LAIC).

scholarly journals On the relaxation of magnetospheric convection when <I>B</I><sub>z</sub> turns northward

2012 ◽  
Vol 30 (6) ◽  
pp. 927-928 ◽  
Author(s):  
M. C. Kelley
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Fields ◽  
Interplanetary Magnetic Field ◽  
Time Constant ◽  
Joule Heat ◽  
Upper Atmosphere ◽  
Joule Dissipation ◽  
Polar Cap ◽  
Magnetospheric Convection

Abstract. The solar wind inputs considerable energy into the upper atmosphere, particularly when the interplanetary magnetic field (IMF) is southward. According to Poynting's theorem (Kelley, 2009), this energy becomes stored as magnetic fields and then is dissipated by Joule heat and by energizing the plasmasheet plasma. If the IMF turns suddenly northward, very little energy is transferred into the system while Joule dissipation continues. In this process, the polar cap potential (PCP) decreases. Experimentally, it was shown many years ago that the energy stored in the magnetosphere begins to decay with a time constant of two hours. Here we use Poynting's theorem to calculate this time constant and find a result that is consistent with the data.

scholarly journals Solar Cycle Variation of Cosmic ray Intensity along with Interplanetary and Solar Wind Plasma Parameters

2008 ◽  
Vol 45 (3) ◽  
pp. 63-68 ◽  
Author(s):  
Rajesh Mishra ◽  
Rekha Agarwal ◽  
Sharad Tiwari
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Cycle ◽  
Interplanetary Magnetic Field ◽  
Cosmic Ray ◽  
Solar Wind Plasma ◽  
Solar Cycles ◽  
Plasma Parameters ◽  
Solar Cycle Variation ◽  
Cosmic Ray Intensity

Solar Cycle Variation of Cosmic ray Intensity along with Interplanetary and Solar Wind Plasma ParametersGalactic cosmic rays are modulated at their propagation in the heliosphere by the effect of the large-scale structure of the interplanetary medium. A comparison of the variations in the cosmic ray intensity data obtained by neutron monitoring stations with those in geomagnetic disturbance, solar wind velocity (V), interplanetary magnetic field (B), and their product (V' B) near the Earth for the period 1964-2004 has been presented so as to establish a possible correlation between them. We used the hourly averaged cosmic ray counts observed with the neutron monitor in Moscow. It is noteworthy that a significant negative correlation has been observed between the interplanetary magnetic field, product (V' B) and cosmic ray intensity during the solar cycles 21 and 22. The solar wind velocity has a good positive correlation with cosmic ray intensity during solar cycle 21, whereas it shows a weak correlation during cycles 20, 22 and 23. The interplanetary magnetic field shows a weak negative correlation with cosmic rays for solar cycle 20, and a good anti-correlation for solar cycles 21-23 with the cosmic ray intensity, which, in turn, shows a good positive correlation with disturbance time index (Dst) during solar cycles 21 and 22, and a weak correlation for cycles 20 and 23.

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.

Measurement of the cosmic ray neutron flux at 4.6 billion volts geomagnetic cutoff rigidity

1965 ◽  
Vol 70 (5) ◽  
pp. 1019-1030 ◽  
Author(s):  
G. Boella ◽  
G. Degli Antoni ◽  
C. Dilworth ◽  
M. Panetti ◽  
L. Scarsi ◽  
...  
Keyword(s):  
Neutron Flux ◽  
Cosmic Ray ◽  
Cutoff Rigidity ◽  
Geomagnetic Cutoff Rigidity ◽  
Geomagnetic Cutoff

Observations of Ultraheavy Cosmic Ray Particles withZ>45 at 10 GV Geomagnetic Cutoff Rigidity

1986 ◽  
Vol 55 (6) ◽  
pp. 2070-2085 ◽  
Author(s):  
Tomoki Yanagimachi ◽  
Tadayoshi Doke ◽  
Ryoji Hamasaki ◽  
Takayoshi Hayashi ◽  
Keizo Hisano ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Cutoff Rigidity ◽  
Geomagnetic Cutoff Rigidity ◽  
Geomagnetic Cutoff

The electron energy spectrum in the flux of galactic cosmic rays

1968 ◽  
Vol 46 (10) ◽  
pp. S518-S521 ◽  
Author(s):  
V. I. Rubtsov ◽  
V. I. Zatsepin
Keyword(s):  
Electron Flux ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Electron Energy Spectrum ◽  
Cutoff Rigidity ◽  
Lead Absorber ◽  
Multiply Charged ◽  
Geomagnetic Cutoff Rigidity ◽  
Geomagnetic Cutoff ◽  
Made In

The primary cosmic-ray electron flux between 3.5 and 80 BeV has been measured with a system composed of scintillation detectors separated by a lead absorber, and with careful discrimination against protons and multiply-charged nuclei. Observations are presented for two balloon flights made in the summer of 1966 at a latitude corresponding to a geomagnetic cutoff rigidity of about 2.5 GV. The results obtained are well represented by a power-law spectrum of the form:[Formula: see text]between 3.5 and 80 BeV. A comparison is made with the results of other investigators.

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