A Cosmic Ray Signature of Equatorial Coronal Holes

2001 ◽  
pp. 13-16
Author(s):  
B. J. I. Bromage ◽  
P. K. Browning ◽  
J. R. Clegg
Keyword(s):  
Coronal Holes ◽  
Cosmic Ray

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

Solar wind temperature–velocity relationship over the last five solar cycles and Forbush decreases associated with different types of interplanetary disturbance

2020 ◽  
Vol 500 (3) ◽  
pp. 2786-2797
Author(s):  
A A Melkumyan ◽  
A V Belov ◽  
M A Abunina ◽  
A A Abunin ◽  
E A Eroshenko ◽  
...  
Keyword(s):  
Solar Wind ◽  
High Speed ◽  
Coronal Holes ◽  
Cosmic Ray ◽  
Magnetic Clouds ◽  
Solar Cycles ◽  
Forbush Decreases ◽  
Proton Temperature ◽  
Interaction Regions ◽  
Interplanetary Disturbance

ABSTRACT The behaviour of the solar wind (SW) proton temperature and velocity and their relationship during Forbush decreases (FDs) associated with various types of solar source – coronal mass ejections (CMEs) and coronal holes (CHs) – have been studied. Analysis of cosmic ray variations, SW temperature, velocity, density, plasma beta, and magnetic field (from 1965–2019) is carried out using three databases: the OMNI database, Variations of Cosmic Rays database (IZMIRAN) and Forbush Effects & Interplanetary Disturbances database (IZMIRAN). Comparison of the observed SW temperature (T) and velocity (V) for the undisturbed SW allows us to derive a formula for the expected SW temperature (Texp, the temperature given by a T–V formula, if V is the observed SW speed). The results reveal a power-law T–V dependence with a steeper slope for low speeds (V < 425 km s−1, exponent = 3.29 ± 0.02) and flatter slope for high speeds (V > 425 km s−1, exponent = 2.25 ± 0.02). A study of changes in the T–V dependence over the last five solar cycles finds that this dependence varies with solar activity. The calculated temperature index KT = T/Texp can be used as an indicator of interplanetary and solar sources of FDs. It usually has abnormally large values in interaction regions of different-speed SW streams and abnormally low values inside magnetic clouds (MCs). The results obtained help us to identify the different kinds of interplanetary disturbance: interplanetary CMEs, sheaths, MCs, corotating interaction regions, high-speed streams from CHs, and mixed events.

scholarly journals Cosmic Ray Signatures of Different Types of Solar Wind Streams

1990 ◽  
Vol 142 ◽  
pp. 259-260
Author(s):  
P.K. Shrivastava ◽  
S.P. Agrawal
Keyword(s):  
Solar Wind ◽  
High Speed ◽  
Solar Wind Speed ◽  
Coronal Holes ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
Wind Speeds ◽  
Different Types ◽  
Speed Solar Wind ◽  
High Speed Solar Wind

The earlier concept of average solar wind speed has changed with time. Besides quiet periods of low/average solar wind speeds, two different kinds of solar sources (solar flares and coronal holes) have been identified to produce high speed solar wind streams. In an earlier investigation, it was reported that the high speed streams associated to these sources produce distinctly different effects on the cosmic ray intensity (Venkatesan, et. al., 1982).

scholarly journals Influence of high-speed streams from coronal holes on cosmic ray intensity in 2007

2013 ◽  
Vol 409 ◽  
pp. 012181 ◽  
Author(s):  
O Kryakunova ◽  
I Tsepakina ◽  
N Nikolayevskiy ◽  
A Malimbayev ◽  
A Belov ◽  
...  
Keyword(s):  
High Speed ◽  
Coronal Holes ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity

scholarly journals MANIFESTATIONS OF TWO BRANCHES OF SOLAR ACTIVITY IN THE HELIOSPHERE AND GCR INTENSITY

2019 ◽  
Vol 5 (4) ◽  
pp. 10-20
Author(s):  
Mikhail Krainev
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Magnetic Fields ◽  
Coronal Holes ◽  
Active Regions ◽  
Cosmic Ray ◽  
Heliospheric Current Sheet ◽  
Field Size ◽  
Galactic Cosmic Ray ◽  
The Magnetic Field

This paper provides insight into heliospheric processes and galactic cosmic ray (GCR) modulation occurring due to the presence of two branches of solar activity in this solar layer. According to the topology of solar magnetic fields, these branches are called toroidal (active regions, sunspots, flares, coronal mass ejections, etc.) and poloidal (high-latitude magnetic fields, polar coronal holes, zonal unipolar magnetic regions, etc.). The main cause of different manifestations of the two branches on the solar surface and in the heliosphere — the layer at the base of the heliosphere in which the main energetic factor is the magnetic field — is formulated. In this case, the magnetic fields of the poloidal branch, which have a larger scale but a lower intensity, gain an advantage in penetrating into the heliosphere. A connection is shown between the poloidal branch and the heliospheric characteristics (solar wind velocity field, size of the heliosphere, form of the heliospheric current sheet, regular heliospheric magnetic field and its fluctuations) that, according to modern notions, determine GCR propagation in the heliosphere.

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 The behaviour of the cosmic-ray equatorial anisotropy inside fast solar-wind streams ejected by coronal holes

1983 ◽  
Vol 6 (5) ◽  
pp. 566-566
Author(s):  
N. Iucci ◽  
M. Parisi ◽  
M. Storini ◽  
G. Villoresi
Keyword(s):  
Solar Wind ◽  
Coronal Holes ◽  
Cosmic Ray ◽  
Fast Solar Wind

Solar-polar coronal holes and the north-south cosmic ray gradient

1978 ◽  
Vol 5 (7) ◽  
pp. 589-591 ◽  
Author(s):  
S. P. Agrawal ◽  
L. J. Lanzerotti ◽  
D. Venkatesan
Keyword(s):  
Coronal Holes ◽  
Cosmic Ray ◽  
The North

The behaviour of the cosmic-ray equatorial anisotropy inside fast solar-wind streams ejected by coronal holes

1983 ◽  
Vol 6 (2) ◽  
pp. 145-158 ◽  
Author(s):  
N. Iucci ◽  
M. Parisi ◽  
M. Storini ◽  
G. Villoresi
Keyword(s):  
Solar Wind ◽  
Coronal Holes ◽  
Cosmic Ray ◽  
Fast Solar Wind
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