scholarly journals Invalid Polar Cap (PC) indices: Erroneous scaling parameters.

2021 ◽  
Author(s):  
P. Stauning
Keyword(s):  
Polar Cap ◽  
Scaling Parameters

scholarly journals Comment on Invariability of relationship between the polar cap magnetic activity and geoeffective interplanetary electric field by Troshichev et al. (2011)

2020 ◽  
Author(s):  
Peter Stauning
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Interplanetary Magnetic Field ◽  
Magnetic Activity ◽  
The Arctic ◽  
Polar Cap ◽  
Antarctic Research Institute ◽  
Scaling Parameters ◽  
Antarctic Research ◽  
Research Institute

Abstract. In the publication Troshichev et al. (2006) on the Polar Cap (PC) indices, PCN (North) and PCS (South), an error was made by using components of the Interplanetary Magnetic Field (IMF) in their Geocentric Solar Ecliptic (GSE) representation instead of the prescribed Geocentric Solar Magnetosphere (GSM) representation for calculations of index scaling parameters in the version AARI_1998-2001 (named AARI#3) issued from the Arctic and Antarctic Research Institute (AARI) in St Petersburg, Russia. The mistake has caused a trail of incorrect relations and wrong conclusions extending since 2006 up to now (2020). The authors of the publication commented here, Troshichev, Podorozhkina, Janzhura (2011): Invariability of relationship between the polar cap magnetic activity and geoeffective interplanetary electric field, Ann. Geophys., 29, 1479-1489, state that they have used scaling parameters of the (invalid) AARI#3 PC index version in their work but have substituted parameters from the more recent AARI_1995-2005 (AARI#4) version instead. The mingling of PC index versions have resulted in erroneous illustrations in their Figs. 1, 2, 3, 6, 7, and 8 and the issuing of non-substantiated statements.

A large rotating structure around AB Doradus A at VLBI scale

2019 ◽  
Vol 15 (S354) ◽  
pp. 189-194
Author(s):  
J. B. Climent ◽  
J. C. Guirado ◽  
R. Azulay ◽  
J. M. Marcaide
Keyword(s):  
Magnetic Reconnection ◽  
Main Sequence ◽  
Complex Structure ◽  
Main Sequence Star ◽  
Polar Cap ◽  
Vlbi Observations ◽  
Rotating Structure ◽  
Source Structure ◽  
Expected Position

AbstractWe report the results of three VLBI observations of the pre-main-sequence star AB Doradus A at 8.4 GHz. With almost three years between consecutive observations, we found a complex structure at the expected position of this star for all epochs. Maps at epochs 2007 and 2010 show a double core-halo morphology while the 2013 map reveals three emission peaks with separations between 5 and 18 stellar radii. Furthermore, all maps show a clear variation of the source structure within the observing time. We consider a number of hypothesis in order to explain such observations, mainly: magnetic reconnection in loops on the polar cap, a more general loop scenario and a close companion to AB Dor A.

scholarly journals Deep Learning Models for Estimation of the SuperDARN Cross Polar Cap Potential

2020 ◽  
Vol 7 (8) ◽  
Author(s):  
Erxiao Liu ◽  
Hongqiao Hu ◽  
Jianjun Liu ◽  
Lei Qiao
Keyword(s):  
Deep Learning ◽  
Learning Models ◽  
Polar Cap ◽  
Cross Polar Cap Potential

scholarly journals An Investigation into the Approximations Used in Wave Packet Molecular Dynamics for the Study of Warm Dense Matter

Plasma ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 294-308
Author(s):  
William A. Angermeier ◽  
Thomas G. White
Keyword(s):  
Molecular Dynamics ◽  
Wave Packet ◽  
Hydrogen Plasma ◽  
Valence Bond ◽  
Dense Matter ◽  
Basis Set ◽  
Warm Dense Matter ◽  
Scaling Parameters ◽  
Oppenheimer Approximation ◽  
Semi Empirical

Wave packet molecular dynamics (WPMD) has recently received a lot of attention as a computationally fast tool with which to study dynamical processes in warm dense matter beyond the Born–Oppenheimer approximation. These techniques, typically, employ many approximations to achieve computational efficiency while implementing semi-empirical scaling parameters to retain accuracy. We investigated three of the main approximations ubiquitous to WPMD: a restricted basis set, approximations to exchange, and the lack of correlation. We examined each of these approximations in regard to atomic and molecular hydrogen in addition to a dense hydrogen plasma. We found that the biggest improvement to WPMD comes from combining a two-Gaussian basis with a semi-empirical correction based on the valence-bond wave function. A single parameter scales this correction to match experimental pressures of dense hydrogen. Ultimately, we found that semi-empirical scaling parameters are necessary to correct for the main approximations in WPMD. However, reducing the scaling parameters for more ab-initio terms gives more accurate results and displays the underlying physics more readily.

scholarly journals Space weather challenges of the polar cap ionosphere

2013 ◽  
Vol 3 ◽  
pp. A02 ◽  
Author(s):  
Jøran Moen ◽  
Kjellmar Oksavik ◽  
Lucilla Alfonsi ◽  
Yvonne Daabakk ◽  
Vineenzo Romano ◽  
...  
Keyword(s):  
Space Weather ◽  
Polar Cap
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