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Plasma Density Structures in the Inner Magnetosphere Derived From RPI Measurements. B. Reinisch 1 , X. Huang 1 , P. Song 1 , P. Nsumei 1 , J. Green 2 , S. Fung 2 , V. Vasyliunas 3 , and D. Gallagher 4 1 University of Massachusetts Lowell 2 NASA Goddard Space Flight Center
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Plasma Density Structures in the Inner Magnetosphere Derived From RPI Measurements B. Reinisch1, X. Huang1, P. Song1, P. Nsumei1, J. Green2, S. Fung2, V. Vasyliunas3, and D. Gallagher4 1University of Massachusetts Lowell 2NASA Goddard Space Flight Center 3Max-Planck Institut für Aeronomie, Lindau 4NASA Marshal Space Flight Center IMAGE Science Meeting 4 June 2003 Lowell, Massachusetts
Areas of Research • Empirical Plasmaspheric density model • 2-D plasmaspheric snapshots • Storm-time depletion and refilling • Polar region model • 2-D polar region snapshots • Magnetospheric field line distortion • Wave propagation theory & method development
Empirical Magnetospheric Density Distribution Average 2000-2001 L = 7 6 5 March 2001 1200 LT June 2001 0800 LT
Profile Fitting Function Ne0 equatorial density flatness (~1) steepness inv invariant latitude
Modeled two dimensional density distribution for MLT=8.0 on June 8, 2001 L=5 L=2
Quiet-time model Measured profile During Storm LS = 2.84
Refilling ratio (Ne0/Ne0,quiet) as function of t and L Storm Full Depleted Full ? Full
X-Trace (b) (a) Figure 2 (a) is a scaled X-mode frequency–virtual range trace and (b) is the derived Ne-true range profile from the trace using the inversion technique described above.
Figure 4 (A) bin-averaged Ne vs. R. The error bars correspond to the Ne standard deviation of densities from each corresponding average, (B) bin-averaged Ne/R vs. Kp, .
RPI Figure 6. Comparison of polar region Ne models [Persoon et al, 1983; Gallagher et al., 2000], DE 1 in-situ particle measurements and the RPI-derived model for Kp = 0, 3,and 5 (along a magnetic latitude of 88).
DES The Arc Length DES for a Dipole Field
R 2 April 2002 0.25 MLT --- LS=3.36, S= -17.1ºR = DES = 2.0
R Normal Conditions9 March 2002 1.71 MLT --- LS= 4.12, S= 3.87ºR = DES = 0.5
R A Stretched Field Line02 Mar 2001 1.85 MLT --- LS= 2.48, lS= -23.5ºR = 2.5, DES = 2.1 = 0.4 Re
R Compressed Field Line23 Mar 2001 13.35 MLT --- LS=3.70, S=37.4ºR = 4.5, DES = 5.2 = - 0.7 Re
Summary • Instantaneous measurement of plasma distribution along geomagnetic field line • method was validated • Database for empirical plasmapheric models and algorithms exist • required are more detailed analyses, L-shell, LT, Dst, SW, IMF dependences • Time series of plasmaspheric filling factor can be used to study storm-time depletion-refilling processes • tested in one case, more storms need be analyzed • 2-D plasmaspheric density snapshots are available • tested two cases, one with convection tail • Polar empirical model for Kp and R developed • Requires studies of Lat., LT, SW, IMF dependences • 2-D polar snapshots show structures • require more event studies, comparison with other instruments (FUV) • Discrepancy between the observed and model predicted field line lengths • require systematic studies • Wave propagation theory • requires further development • Density inversion for Z mode traces? • Can it be done?