Polar Coronal Holes and Cosmic-Ray Modulation

Science ◽  
1980 ◽  
Vol 207 (4432) ◽  
pp. 761-763 ◽  
Author(s):  
A. J. HUNDHAUSEN ◽  
D. G. SIME ◽  
R. T. HANSEN ◽  
S. F. HANSEN
Keyword(s):  
Coronal Holes ◽  
Cosmic Ray ◽  
Cosmic Ray Modulation

scholarly journals Effects of the solar wind termination shock and heliosheath on theheliospheric modulation of galactic and anomalous Helium

2004 ◽  
Vol 22 (8) ◽  
pp. 3063-3072 ◽  
Author(s):  
U. W. Langner ◽  
M. S. Potgieter
Keyword(s):  
Solar Wind ◽  
Cosmic Ray ◽  
Magnetic Polarity ◽  
Termination Shock ◽  
Shock Acceleration ◽  
Diffusive Shock Acceleration ◽  
Cosmic Ray Modulation ◽  
Low Energies ◽  
Solar Wind Termination Shock ◽  
Charge Sign

Abstract. The interest in the role of the solar wind termination shock and heliosheath in cosmic ray modulation studies has increased significantly as the Voyager 1 and 2 spacecraft approach the estimated position of the solar wind termination shock. The effect of the solar wind termination shock on charge-sign dependent modulation, as is experienced by galactic cosmic ray Helium (He++) and anomalous Helium (He+), is the main topic of this work, and is complementary to the previous work on protons, anti-protons, electrons, and positrons. The modulation of galactic and anomalous Helium is studied with a numerical model including a more fundamental and comprehensive set of diffusion coefficients, a solar wind termination shock with diffusive shock acceleration, a heliosheath and particle drifts. The model allows a comparison of modulation with and without a solar wind termination shock and is applicable to a number of cosmic ray species during both magnetic polarity cycles of the Sun. The modulation of Helium, including an anomalous component, is also done to establish charge-sign dependence at low energies. We found that the heliosheath is important for cosmic ray modulation and that its effect on modulation is very similar for protons and Helium. The local Helium interstellar spectrum may not be known at energies

Heliocentric radius of the cosmic ray modulation boundary

1986 ◽  
Vol 13 (7) ◽  
pp. 628-631 ◽  
Author(s):  
B. A. Randall ◽  
J. A. Van Allen
Keyword(s):  
Cosmic Ray ◽  
Cosmic Ray Modulation

scholarly journals Heliospheric modulation of cosmic rays: model and observation

2017 ◽  
Vol 3 (1) ◽  
pp. 63-78
Author(s):  
Сардаана Герасимова ◽  
Sardaana Gerasimova ◽  
Петр Гололобов ◽  
Peter Gololobov ◽  
Владислав Григорьев ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Wide Energy Range ◽  
Interstellar Gas ◽  
Cosmic Ray Intensity ◽  
Basic Model ◽  
Electrical Neutrality ◽  
Cosmic Ray Modulation ◽  
Wide Energy ◽  
Activity Cycles ◽  
Zero Potential

This paper presents the basic model of cosmic ray modulation in the heliosphere, developed in Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy of the Siberian Branch of RAS. The model has only one free modulation parameter: the ratio of the regular magnetic field to the turbulent one. It may also be applied to the description of cosmic ray intensity variations in a wide energy range from 100 MeV to 100 GeV. Possible mechanisms of generation of the mentioned turbulence field are considered. The primary assumption about the electrical neutrality of the heliosphere appears to be wrong, and the zero potential needed to match the model with observations in the plane of the solar equator can be achieved if the frontal point of the heliosphere, which is flowed around by interstellar gas, lies near the mentioned plane. We have revealed that the abnormal rise of cosmic ray intensity at the end of solar cycle 23 is related to the residual modulation produced by the subsonic solar wind behind the front of a standing shock wave. The model is used to describe features of cosmic ray intensity variations in several solar activity cycles.

Solar polar coronal holes and galactic cosmic ray intensities

1980 ◽  
Vol 85 (A12) ◽  
pp. 6845 ◽  
Author(s):  
S. P. Agrawal ◽  
L. J. Lanzerotti ◽  
D. Venkatesan ◽  
R. T. Hansen
Keyword(s):  
Coronal Holes ◽  
Cosmic Ray ◽  
Galactic Cosmic Ray

Change in the rigidity dependence of the galactic cosmic ray modulation in 2008–2009

2012 ◽  
Vol 49 (4) ◽  
pp. 784-790 ◽  
Author(s):  
G.A. Bazilevskaya ◽  
M.B. Krainev ◽  
V.S. Makhmutov ◽  
Yu.I. Stozhkov ◽  
A.K. Svirzhevskaya ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Cosmic Ray Modulation ◽  
Galactic Cosmic Ray ◽  
Rigidity Dependence
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