Estimation of radial gradients of phase space density from POLAR observations during a quiet period prior to a sudden solar wind dynamic pressure enhancement

2010 ◽  
Vol 115 (A12) ◽  
pp. n/a-n/a ◽  
Author(s):  
H.-J. Kim ◽  
E. Zesta ◽  
K.-C. Kim ◽  
Y. Shprits ◽  
Y. Shi ◽  
...  
Keyword(s):  
Solar Wind ◽  
Phase Space ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Phase Space Density ◽  
Quiet Period ◽  
Space Density

scholarly journals The use of iron charge state changes as a tracer for solar wind entry and energization within the magnetosphere

2003 ◽  
Vol 21 (11) ◽  
pp. 2155-2164 ◽  
Author(s):  
T. A. Fritz ◽  
T. H. Zurbuchen ◽  
G. Gloeckler ◽  
S. Hefti ◽  
J. Chen
Keyword(s):  
Solar Wind ◽  
Phase Space ◽  
Charge State ◽  
Time Scales ◽  
High Latitude ◽  
Libration Point ◽  
Average Charge ◽  
Phase Space Density ◽  
Space Density ◽  
Magnetospheric Configuration And Dynamics

Abstract. The variation of the charge state of iron [Fe] ions is used to trace volume elements of plasma in the solar wind into the magnetosphere and to determine the time scales associated with the entry into and the action of the magnetospheric energization process working on these plasmas. On 2–3 May 1998 the Advanced Composition Explorer (ACE) spacecraft located at the L1 libration point observed a series of changes to the average charge state of the element Fe in the solar wind plasma reflecting variation in the coronal temperature of their original source. Over the period of these two days the average Fe charge state was observed to vary from + 15 to + 6 both at the Polar satellite in the high latitude dayside magnetosphere and at ACE. During a period of southward IMF the observations at Polar inside the magnetosphere of the same Fe charge state were simultaneous with those at ACE delayed by the measured convection speed of the solar wind to the subsolar magnetopause. Comparing the phase space density as a function of energy at both ACE and Polar has indicated that significant energization of the plasma occurred on very rapid time scales. Energization at constant phase space density by a factor of 5 to 10 was observed over a range of energy from a few keV to about 1 MeV. For a detector with a fixed energy threshold in the range from 10 keV to a few hundred keV this observed energization will appear as a factor of ~103 increase in its counting rate. Polar observations of very energetic O+ ions at the same time indicate that this energization process must be occurring in the high latitude cusp region inside the magnetosphere and that it is capable of energizing ionospheric ions at the same time.Key words. Magnetospheric physics (magnetopause, cusp, and boundary layers; magnetospheric configuration and dynamics; solar wind-magnetosphere interactions)

scholarly journals Features of energetic particle radial profiles inferred from geosynchronous responses to solar wind dynamic pressure enhancements

2009 ◽  
Vol 27 (2) ◽  
pp. 851-859 ◽  
Author(s):  
Y. Shi ◽  
E. Zesta ◽  
L. R. Lyons
Keyword(s):  
Magnetic Field ◽  
Phase Space ◽  
Dynamic Pressure ◽  
Radial Profile ◽  
Radial Distance ◽  
Geosynchronous Orbit ◽  
Relativistic Electrons ◽  
Phase Space Density ◽  
Space Density ◽  
Flux Response

Abstract. Determination of the radial profile of phase space density of relativistic electrons at constant adiabatic invariants is crucial for identifying the source for them within the outer radiation belt. The commonly used method is to convert flux observed at fixed energy to phase space density at constant first, second and third adiabatic invariants, which requires an empirical global magnetic field model and thus might produce some uncertainties in the final results. From a different perspective, in this paper we indirectly infer the shape of the radial profile of phase space density of relativistic electrons near the geosynchronous region by statistically examining the geosynchronous energetic flux response to 128 solar wind dynamic pressure enhancements during the years 2000 to 2003. We thus avoid the disadvantage of using empirical magnetic field models. Our results show that the flux response is species and energy dependent. For protons and low-energy electrons, the primary response to magnetospheric compression is an increase in flux at geosynchronous orbit. For relativistic electrons, the dominant response is a decrease in flux, which implies that the phase space density decreases toward increasing radial distance at geosynchronous orbit and leads to a local peak inside of geosynchronous orbit. The flux response of protons and non-relativistic electrons could result from a phase density that increases toward increasing radial distance, but this cannot be determined for sure due to the particle energization associated with pressure enhancements. Our results for relativistic electrons are consistent with previous results obtained using magnetic field models, thus providing additional confirmation that these results are correct and indicating that they are not the result of errors in their selected magnetic field model.

Solar wind dynamic pressure enhancements and polar auroras

1998 ◽  
Vol 22 (9) ◽  
pp. 1305-1308 ◽  
Author(s):  
Y Zhang ◽  
D.J McEwen ◽  
I Oznovich
Keyword(s):  
Solar Wind ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure

Statistical study of the effect of solar wind dynamic pressure fronts on the dayside and nightside ionospheric convection

2011 ◽  
Vol 116 (A10) ◽  
pp. n/a-n/a ◽  
Author(s):  
A. Boudouridis ◽  
L. R. Lyons ◽  
E. Zesta ◽  
J. M. Weygand ◽  
A. J. Ribeiro ◽  
...  
Keyword(s):  
Solar Wind ◽  
Statistical Study ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Ionospheric Convection
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