TY - JOUR

T1 - STRUCTURE OF THE INNER PLASMA SHEET AT MIDNIGHT DURING STEADY CONVECTION

AU - Sergeev, V.A.

AU - APARICIO, B

AU - PERRAUT, S

AU - MALKOV, MV

AU - PELLINEN, RJ

PY - 1991/8

Y1 - 1991/8

N2 - On 19 February 1978 (19:00-22:000 U.T.) GEOS-1 spacecraft crossed at equatorial latitudes at midnight the inner domain of the plasma sheet (L = 3-7) after a long period of steady magnetospheric convection (lasting congruent-to 8 h). A magnetic field model was chosen in agreement with the in situ magnetic field measurements. Simultaneous ground-based observations in the nearly conjugate region were used to control both the electric field and the precipitation patterns. Plasma measurements on board GEOS-1 displayed a systematic radial structure. The inner edge of the auroral protons was earthwards of the sharp plasmapause showing a well-ordered nose-like energy dispersion pattern. The auroral electrons appeared tailwards of the plasmapause. The ordinary monotonic energy dispersion pattern was superimposed by the impulsive flux variations correlated with signatures of short transient injections (inferred from ground-based and mid-tail data). The whole gross pattern of 1-20 keV proton and electron inner edges was found to be in good quantitative agreement with the predictions of Ejiri's calculations of single particle drifts in the Volland-Stern electric field pattern whose intensity was chosen to satisfy the observed position of the plasmapause. It was also shown that precipitation is an important factor for electrons which indeed influence the position of the electron inner edge. The use of a realistic magnetotail model allowed us to compare the precipitation pattern and the plasma regimes in the midnight plasma sheet by mapping these different regions. The diffuse (CPS type) precipitation was found in the flux tubes of the inner magnetosphere containing the maximum intensity of the electron energy flux at the equator. We also argued from mapping results that: the discrete (BPS type) precipitation corresponds to the BLPS region of the plasma sheet; and the CPS region of the plasma sheet at 10-20 R(E) is projected to the low-level precipitation region separating the zones of intense diffuse and discrete precipitations.

AB - On 19 February 1978 (19:00-22:000 U.T.) GEOS-1 spacecraft crossed at equatorial latitudes at midnight the inner domain of the plasma sheet (L = 3-7) after a long period of steady magnetospheric convection (lasting congruent-to 8 h). A magnetic field model was chosen in agreement with the in situ magnetic field measurements. Simultaneous ground-based observations in the nearly conjugate region were used to control both the electric field and the precipitation patterns. Plasma measurements on board GEOS-1 displayed a systematic radial structure. The inner edge of the auroral protons was earthwards of the sharp plasmapause showing a well-ordered nose-like energy dispersion pattern. The auroral electrons appeared tailwards of the plasmapause. The ordinary monotonic energy dispersion pattern was superimposed by the impulsive flux variations correlated with signatures of short transient injections (inferred from ground-based and mid-tail data). The whole gross pattern of 1-20 keV proton and electron inner edges was found to be in good quantitative agreement with the predictions of Ejiri's calculations of single particle drifts in the Volland-Stern electric field pattern whose intensity was chosen to satisfy the observed position of the plasmapause. It was also shown that precipitation is an important factor for electrons which indeed influence the position of the electron inner edge. The use of a realistic magnetotail model allowed us to compare the precipitation pattern and the plasma regimes in the midnight plasma sheet by mapping these different regions. The diffuse (CPS type) precipitation was found in the flux tubes of the inner magnetosphere containing the maximum intensity of the electron energy flux at the equator. We also argued from mapping results that: the discrete (BPS type) precipitation corresponds to the BLPS region of the plasma sheet; and the CPS region of the plasma sheet at 10-20 R(E) is projected to the low-level precipitation region separating the zones of intense diffuse and discrete precipitations.

KW - MAGNETOSPHERIC CONVECTION

KW - DIFFUSE AURORA

KW - ELECTRON-PRECIPITATION

KW - ION PRECIPITATION

KW - MLT SECTOR

KW - FIELD

KW - BOUNDARY

KW - SUBSTORM

KW - EQUATOR

KW - FLUXES

U2 - 10.1016/0032-0633(91)90159-8

DO - 10.1016/0032-0633(91)90159-8

M3 - статья

VL - 39

SP - 1083

EP - 1096

JO - Planetary and Space Science

JF - Planetary and Space Science

SN - 0032-0633

IS - 8

ER -