Open AccessIonospheric and thermospheric variations associated with prompt penetration electric fields
Author(s) -
Lu G.,
Goncharenko L.,
Nicolls M. J.,
Maute A.,
Coster A.,
Paxton L. J.
Publication year - 2012
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2012ja017769
Subject(s) - thermosphere , ionosphere , f region , electric field , tec , atmospheric sciences , plasmasphere , daytime , equator , geophysics , earth's magnetic field , magnetic dip , middle latitudes , field line , incoherent scatter , latitude , local time , electron density , electron precipitation , geology , physics , magnetosphere , electron , plasma , geodesy , magnetic field , statistics , mathematics , quantum mechanics
This paper presents a comprehensive modeling investigation of ionospheric and thermospheric variations during a prompt penetration electric field (PPEF) event that took place on 9 November 2004, using the Thermosphere‐Ionosphere‐Mesosphere Electrodynamic General Circulation Model (TIMEGCM). The simulation results reveal complex latitudinal and longitudinal/local‐time variations in vertical ion drift in the middle‐ and low‐latitude regions owing to the competing influences of electric fields and neutral winds. It is found that electric fields are the dominant driver of vertical ion drift at the magnetic equator; at midlatitudes, however, vertical ion drift driven by disturbance meridional winds exceeds that driven by electric fields. The temporal evolution of the UT‐latitude electron density profile from the simulation depicts clearly a super‐fountain effect caused by the PPEF, including the initial slow‐rise of the equatorial F‐layer peak height, the split of the F‐layer peak density, and the subsequent downward diffusion of the density peaks along magnetic field lines. Correspondingly, low‐latitude total electron content (TEC) becomes bifurcated around the magnetic equator. The O/N 2 column density ratio, on the other hand, shows very little variations during this PPEF event, excluding composition change as a potential mechanism for the TEC variations. By using realistic, time‐dependent, high‐latitude electric potential and auroral precipitation patterns to drive the TIMEGCM, the model is able to successfully reproduce the large vertical ion drift of ∼120 m/s over the Jicamarca incoherent radar (IS) in Peru, which is the largest daytime ion drift ever recorded by the radar. The simulation results are validated with several key observations from IS radars, ground GPS‐TEC network, and the TIMED‐GUVI O/N 2 column density ratio. The model‐data intercomparison also reveals some deficiencies in the TIMEGCM, particularly the limitations imposed by its upper boundary height as well as the prescribed O + flux.