A statistical characterization of plasmasphere density structure and boundary locations

Journal Article · Fri Jun 01 04:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA095iA06p07937· OSTI ID:5376457

Horwitz, J L; Comfort, R H ^[1]; Chappell, C R ^[2]

---

1. Univ. of Alabama, Huntsville (USA)
2. Marshall Space Flight Center, Huntsville, AL (USA)

A statistical study of plasmaspheric density profiles and their boundaries is performed, using measurements of core (<50 eV) ions by the retarding ion mass spectrometer (RIMS) on Dynamics Explorer 1. The plasmasphere density profiles are classified into essentially six different categories, indicative of density structure out to the outer boundary of observable cold, isotropic plasma. The most common profiles observed are those which are relatively featureless out to this outer boundary and those which exhibit multiple plateaus and plasmapauses. the multiple plateau profiles occur predominantly in the afternoon and evening sectors, while the featureless profiles are most common in the midnight through morning sectors. In the multiple plateau profiles, the average MLT (magnetic local time)-L locus of the inner plasmapause gradients is nearly circular at L = 3-4. Profiles with significant density troughs occur most often in the evening sector, and the troughs are widest in this sector as well. The MLT-L local time shape of the outer boundary of RIMS-observed cold ions (termed here low-energy ion transition, or LEIT) is similar to previously reported average plasmapause shapes, though its bulge region occurs in the afternoon sector. This MLT-L shape also tends to become more circular with increasing geomagnetic activity. Using simultaneous plasma density measurements from the plasma wave instrument, it is found that the LEIT typically is located between densities of 10 and 100 cm{sup {minus}3}, with an average plasma density there of about 60 cm{sup {minus}3}.

• OSTI ID: 5376457
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:A6; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
&amp; Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COLD PLASMA
CONVECTION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ENERGY TRANSFER
EXPLORER SATELLITES
FUNCTIONS
HEAT TRANSFER
MAGNETIC STORMS
MASS TRANSFER
MATHEMATICS
MORPHOLOGY
PLASMA
PLASMA DENSITY
PLASMA WAVES
PLASMASPHERE
RESPONSE FUNCTIONS
SATELLITES
SEASONAL VARIATIONS
STATISTICS
VARIATIONS