scholarly journals The Common Spectrum for Accelerated Ions in the Quiet-Time Solar Wind

2006 ◽  
Vol 640 (1) ◽  
pp. L79-L82 ◽  
Author(s):  
L. A. Fisk ◽  
G. Gloeckler
Keyword(s):  
Solar Wind ◽  
Quiet Time ◽  
The Common

scholarly journals Total electron content responses to HILDCAAs and geomagnetic storms over South America

2017 ◽  
Vol 35 (6) ◽  
pp. 1309-1326 ◽  
Author(s):  
Patricia Mara de Siqueira Negreti ◽  
Eurico Rodrigues de Paula ◽  
Claudia Maria Nicoli Candido
Keyword(s):  
Solar Wind ◽  
South America ◽  
Total Electron Content ◽  
Geomagnetic Storm ◽  
Electric Fields ◽  
Geomagnetic Storms ◽  
Time Variability ◽  
Electron Content ◽  
Quiet Time ◽  
Total Electron

Abstract. Total electron content (TEC) is extensively used to monitor the ionospheric behavior under geomagnetically quiet and disturbed conditions. This subject is of greatest importance for space weather applications. Under disturbed conditions the two main sources of electric fields, which are responsible for changes in the plasma drifts and for current perturbations, are the short-lived prompt penetration electric fields (PPEFs) and the longer-lasting ionospheric disturbance dynamo (DD) electric fields. Both mechanisms modulate the TEC around the globe and the equatorial ionization anomaly (EIA) at low latitudes. In this work we computed vertical absolute TEC over the low latitude of South America. The analysis was performed considering HILDCAA (high-intensity, long-duration, continuous auroral electrojet (AE) activity) events and geomagnetic storms. The characteristics of storm-time TEC and HILDCAA-associated TEC will be presented and discussed. For both case studies presented in this work (March and August 2013) the HILDCAA event follows a geomagnetic storm, and then a global scenario of geomagnetic disturbances will be discussed. Solar wind parameters, geomagnetic indices, O ∕ N2 ratios retrieved by GUVI instrument onboard the TIMED satellite and TEC observations will be analyzed and discussed. Data from the RBMC/IBGE (Brazil) and IGS GNSS networks were used to calculate TEC over South America. We show that a HILDCAA event may generate larger TEC differences compared to the TEC observed during the main phase of the precedent geomagnetic storm; thus, a HILDCAA event may be more effective for ionospheric response in comparison to moderate geomagnetic storms, considering the seasonal conditions. During the August HILDCAA event, TEC enhancements from  ∼  25 to 80 % (compared to quiet time) were observed. These enhancements are much higher than the quiet-time variability observed in the ionosphere. We show that ionosphere is quite sensitive to solar wind forcing and considering the events studied here, this was the most important source of ionospheric responses. Furthermore, the most important source of TEC changes were the long-lasting PPEFs observed on August 2013, during the HILDCAA event. The importance of this study relies on the peculiarity of the region analyzed characterized by high declination angle and ionospheric gradients which are responsible for creating a complex response during disturbed periods.

Quiet-time solar wind superhalo electrons at solar minimum

2013 ◽  
Author(s):  
Linghua Wang ◽  
Robert P. Lin ◽  
Chadi Salem ◽  
Marc Pulupa ◽  
Davin E. Larson ◽  
...  
Keyword(s):  
Solar Wind ◽  
Solar Minimum ◽  
Quiet Time

scholarly journals Spacecraft potential effects on electron moments derived from a perfect plasma detector

2004 ◽  
Vol 22 (6) ◽  
pp. 2073-2080 ◽  
Author(s):  
V. Génot ◽  
S. J. Schwartz
Keyword(s):  
Solar Wind ◽  
Lower Energy ◽  
Particle Temperature ◽  
Common Value ◽  
Spacecraft Potential ◽  
Energy Cutoff ◽  
Complete Computation ◽  
The Common ◽  
Measured Density

Abstract. A complete computation of the effect of the spacecraft potential on electron moments is presented. We adopt the perfect detector concept to estimate how measured density, velocity and temperature are affected by the constraints imposed by the detector, such as the finite lower energy cutoff and the spacecraft potential. We investigate the role of the potential in different plasma regimes usually crossed by satellites. It appears that the solar wind is the region where the moments are most compromised, as the particle temperature is low. To a lesser extent the moments calculated in the magnetosheath may also deviate from the real moments, displaying up to 40% overestimation for the density under typical detector operation. The analysis allows us to identify a range of spacecraft potential values which minimizes the variation in the estimation; it is found that it corresponds to the common value adopted by potential controlling experiments.

scholarly journals Quiet-time Solar Wind Suprathermal Electrons of Different Solar Origins

2020 ◽  
Vol 896 (1) ◽  
pp. L5
Author(s):  
Liu Yang ◽  
Linghua Wang ◽  
Liang Zhao ◽  
Jiawei Tao ◽  
Gang Li ◽  
...  
Keyword(s):  
Solar Wind ◽  
Quiet Time ◽  
Suprathermal Electrons

Numerical Simulation on the Propagation and Deflection of Fast Coronal Mass Ejections (CMEs) Interacting with a Corotating Interaction Region in Interplanetary Space

2020 ◽  
Author(s):  
Fang Shen ◽  
Yousheng Liu ◽  
Yi Yang
Keyword(s):  
Solar Wind ◽  
Coronal Mass Ejections ◽  
Interplanetary Space ◽  
Three Dimensional ◽  
Flux Rope ◽  
Interaction Region ◽  
The Sun ◽  
Corotating Interaction Region ◽  
The Common ◽  
Wind Flows

<p>Previous research has shown that the deflection of coronal mass ejections (CMEs) in interplanetary space, especially fast CMEs, is a common phenomenon. The deflection caused by the interaction with background solar wind is an important factor to determine whether CMEs could hit Earth or not. As the Sun rotates, there will be interactions between solar wind flows with different speeds. When faster solar wind runs into slower solar wind<br>ahead, it will form a compressive area corotating with the Sun, which is called a corotating interaction region (CIR). These compression regions always have a higher density than the common background solar wind. When interacting with CME, will this make a difference in the deflection process of CME? In this research, first, a three-dimensional (3D) flux-rope CME initialization model is established based on the graduated cylindrical shell (GCS)<br>model. Then this CME model is introduced into the background solar wind, which is obtained using a 3D IN (INterplanetary) -TVD-MHD model. The Carrington Rotation (CR) 2154 is selected as an example to simulate the propagation and deflection of fast CME when it interacts with background solar wind, especially with the CIR structure.</p><p>The simulation results show that: (1) the fast CME will deflect eastward when it propagates into the background solar wind without the CIR; (2) when the fast CME hits the CIR on its west side, it will also deflect eastward, and the deflection angle will increase compared with the situation without CIR.</p>

scholarly journals Anomalous Forbush effects from sources far from Sun center

2008 ◽  
Vol 4 (S257) ◽  
pp. 451-456
Author(s):  
E. Eroshenko ◽  
A. Belov ◽  
H. Mavromichalaki ◽  
V. Oleneva ◽  
A. Papaioannou ◽  
...  
Keyword(s):  
Solar Wind ◽  
Cosmic Ray ◽  
The Sun ◽  
Geomagnetic Disturbances ◽  
Cosmic Ray Intensity ◽  
The Earth ◽  
The Common ◽  
Solar Wind Parameters ◽  
Significant Disturbance ◽  
Forbush Effect

AbstractThe Forbush effects associated with far western and eastern powerful sources on the Sun that occurred on the background of unsettled and moderate interplanetary and geomagnetic disturbances have been studied by data from neutron monitor networks and relevant measurements of the solar wind parameters. These Forbush effects may be referred to a special sub-class of events, with the characteristics like the event in July 2005, and incorporated by the common conditions: absence of a significant disturbance in the Earth vicinity; absence of a strong geomagnetic storm; slow decrease of cosmic ray intensity during the main phase of the Forbush effect. General features and separate properties in behavior of density and anisotropy of 10 GV cosmic rays for this subclass are investigated.

Quiet-time solar-wind ionic composition

1981 ◽  
Vol 4 (6) ◽  
pp. 682-697 ◽  
Author(s):  
V. Formisano ◽  
S. Orsini
Keyword(s):  
Solar Wind ◽  
Ionic Composition ◽  
Quiet Time

Identification of the ground signatures of magnetospheric current systems as a function of latitude during intense magnetic storms

2021 ◽  
Author(s):  
Vasilis Pitsis ◽  
Georgios Balasis ◽  
Ioannis Daglis ◽  
Dimitris Vassiliadis
Keyword(s):  
Solar Wind ◽  
Magnetic Fields ◽  
Geomagnetic Field ◽  
Ring Current ◽  
Magnetic Storms ◽  
Quiet Time ◽  
Maximum Correlation ◽  
Current Form ◽  
H Index ◽  
Current Systems

<p>We show that changes in the magnetospheric ring current and auroral currents during the magnetic storms of March 2015 and June 2015, are recorded in several specific ways by ground magnetometers. The ring current changes are detected in geomagnetic field measurements of ground stations at magnetic mid-latitudes from -50 to +50 degrees. The auroral currents changes are detected at high magnetic latitudes from 50 to about 73 degrees. Finally, for stations between 73 and about 85 degrees the measurements of the ground magnetometers seem to be directly correlated with the convection electric field VB<sub>South</sub> of the solar wind. Using the correlations among magnetic fields measured at stations ordered by latitude, a correlation diagram is obtained where the maximum correlation values for fields determined by the ring current form a distinct block. High-latitude magnetic fields from stations at higher latitudes, which are mainly determined by auroral currents, form a different block in the same diagram. This is in agreement with our earlier work using wavelet transforms on ground magnetic-field time series, where mid-latitude fields stations that are influenced mainly by the ring current, give a critical exponent greater than 2 while higher-latitude fields show a more complex dependence with two exponents. The maximum correlation values for mid-latitude fields correlated with the SYM-H index vary from 0.8 to 0.9, and, thus, we infer that those geomagnetic disturbances are mainly due to the ring current. The maximum correlations between the same fields and the solar wind VB<sub>South </sub>vary from 0.5 to 0.7. Fields at magnetic latitudes between 50 and 73 degrees exhibit greater correlation values for the AL index rather than the SYM-H index. This is expected since in the auroral zone, the convection- and substorm-associated auroral electrojets contribute significantly to the deviation of the geomagnetic field from its quiet-time value. In this case, maximum correlations vary between 0.6 and 0.7 for auroral latitude stations when compared with AL, as opposed to 0.4–0.5 when compared with SYM-H. Our results show how different measures of ground geomagnetic variations reflect the time evolution of several magnetospheric current systems and of the solar wind – magnetosphere coupling.</p>

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