scholarly journals Suprathermal Ion Abundance Variations in Corotating Interaction Regions over Two Solar Cycles

2019 ◽  
Vol 883 (1) ◽  
pp. L10 ◽  
Author(s):  
Robert C. Allen ◽  
George C. Ho ◽  
Glenn M. Mason
Keyword(s):  
Solar Cycles ◽  
Corotating Interaction Regions ◽  
Interaction Regions

scholarly journals Comparative statistical study of characteristics of plasma in planar and non-planar ICME sheaths during solar cycles 23 and 24

2020 ◽  
Vol 494 (2) ◽  
pp. 2498-2508 ◽  
Author(s):  
Zubair I Shaikh ◽  
Anil N Raghav ◽  
Geeta Vichare ◽  
Ankush Bhaskar ◽  
Wageesh Mishra
Keyword(s):  
Statistical Study ◽  
Plasma Temperature ◽  
Solar Cycles ◽  
Interplanetary Coronal Mass Ejections ◽  
Plasma Properties ◽  
Corotating Interaction Regions ◽  
Magnetic Structures ◽  
In Situ Data ◽  
Interaction Regions

ABSTRACT Planar magnetic structures (PMS) are often observed in sheath regions driven by interplanetary coronal mass ejections (ICMEs) and in corotating interaction regions (CIRs). Here, we study plasma properties statistically within planar and non-planar ICME sheath regions using in situ data from the Advanced Composition Explore (ACE) spacecraft. The study includes 420 ICME-driven sheaths from 1998–2017. We found that 146 ($\sim 35{{\ \rm per\ cent}}$) ICME-driven sheaths are planar, whereas 274 ($\sim 65{{\ \rm per\ cent}}$) are non-planar. This study found that the average plasma temperature, density, speed, plasma beta, thermal pressure and magnetic pressure are higher in planar sheaths than in non-planar sheaths. This implies that high compression plays an essential role in the formation of PMS in sheath regions. Interestingly, our analysis reveals explicitly that the strength of the southward/northward magnetic field component is almost double in planar sheath regions compared with non-planar sheath regions. This suggests that planar sheaths are more geoeffective than non-planar sheaths.

scholarly journals Corotating Interaction Regions as Seen by the STEREO Heliospheric Imagers 2007 – 2010

Solar Physics ◽  
2015 ◽  
Vol 290 (8) ◽  
pp. 2291-2309 ◽  
Author(s):  
T. M. Conlon ◽  
S. E. Milan ◽  
J. A. Davies ◽  
A. O. Williams
Keyword(s):  
Corotating Interaction Regions ◽  
Interaction Regions

Study of Corotating Interaction Regions in the Ascending Phase of the Solar Cycle: Multi-spacecraft Observations

Solar Physics ◽  
2013 ◽  
Vol 285 (1-2) ◽  
pp. 201-216 ◽  
Author(s):  
J. A. Gonzalez-Esparza ◽  
E. Romero-Hernandez ◽  
P. Riley
Keyword(s):  
Solar Cycle ◽  
Corotating Interaction Regions ◽  
Interaction Regions

scholarly journals On the origin of variable structures in the winds of hot luminous stars

2013 ◽  
Vol 440 (1) ◽  
pp. 2-9 ◽  
Author(s):  
Yannick J. L. Michaux ◽  
Anthony F. J. Moffat ◽  
André-Nicolas Chené ◽  
Nicole St-Louis
Keyword(s):  
Magnetic Field ◽  
Empirical Evidence ◽  
Temporal Variability ◽  
Large Scale ◽  
Small Scale ◽  
Ionization Zone ◽  
Corotating Interaction Regions ◽  
Wind Variability ◽  
Global Magnetic Field ◽  
Interaction Regions

Abstract Examination of the temporal variability properties of several strong optical recombination lines in a large sample of Galactic Wolf–Rayet (WR) stars reveals possible trends, especially in the more homogeneous WC than the diverse WN subtypes, of increasing wind variability with cooler subtypes. This could imply that a serious contender for the driver of the variations is stochastic, magnetic subsurface convection associated with the 170 kK partial-ionization zone of iron, which should occupy a deeper and larger zone of greater mass in cooler WR subtypes. This empirical evidence suggests that the heretofore proposed ubiquitous driver of wind variability, radiative instabilities, may not be the only mechanism playing a role in the stochastic multiple small-scaled structures seen in the winds of hot luminous stars. In addition to small-scale stochastic behaviour, subsurface convection guided by a global magnetic field with localized emerging loops may also be at the origin of the large-scale corotating interaction regions as seen frequently in O stars and occasionally in the winds of their descendant WR stars.

Muon and neutron observations in connection with the corotating interaction regions

2007 ◽  
Vol 40 (3) ◽  
pp. 348-352 ◽  
Author(s):  
M.R. Da Silva ◽  
A. Dal Lago ◽  
E. Echer ◽  
A. de Lucas ◽  
W.D. Gonzalez ◽  
...  
Keyword(s):  
Corotating Interaction Regions ◽  
Interaction Regions
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