Simulation study of penetration electric field effects on the low‐ to mid‐latitude ionosphere

Huba, J. D.; Joyce, G.; Sazykin, S.; Wolf, R. A.; Spiro, R. W.

doi:10.1029/2005gl024162

Cited by 101 publications

(111 citation statements)

References 19 publications

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“…We plan to use this framework to develop algorithms for operational systems support for AFRL's global Scintillation Network Decision Aid system [Groves et al, 1997]. It is hoped that these significant findings will also be incorporated in global magnetosphere-ionosphere-thermosphere coupled models currently under development [Maruyama et al, 2005;Huba et al, 2005;Lin et al, 2005].…”

Section: Discussionmentioning

confidence: 99%

Response of the equatorial ionosphere at dusk to penetration electric fields during intense magnetic storms

et al. 2007

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different aspects of which have been widely studied by the community. We present here a very complete set of space and ground-based diagnostics that provide the vertical and latitudinal structures of the ionosphere within the South Atlantic magnetic anomaly (SAMA) region and the contiguous parts of South America and Africa. We show that for both storms, the dusk sector corresponding to the universal time (UT) interval between the fast decrease of the SYM-H index and minimum SYM-H value determines uniquely the longitude interval populated by equatorial plasma bubbles and depletions. Further, we find that the UT of these storms is such that the ionospheric density perturbations occur in the SAMA region, which are most extended in latitude and altitude compared with other regions of the globe. In the dusk sector, the eastward penetration electric field, associated with rapid SYM-H decrease, adds to the postsunset eastward E-field because of the F region dynamo, which may be specially enhanced in this longitude interval because of the increased zonal conductivity gradient caused by energetic particle precipitation. This enhanced E-field at dusk causes a rapid uplift of the ionosphere and sets off plasma instabilities to form bubbles or bite-outs. The decreased ion density seen in the Defense Meteorological Satellite Program (DMSP) in situ data at 840 km indicates that the ionospheric plasma has been lifted above the DMSP altitude and transported away from the region by diffusion along magnetic field lines. Plasma bubbles and bite-outs impact satellite communication and navigation systems by introducing scintillations and steep density gradients. This paper corroborates that intense magnetic storms follow the framework, developed by Su. Basu et al. (2001) for moderate storms, that specifies the longitude interval in which such disturbances are most likely to occur.

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Section: Discussionmentioning

confidence: 99%

Response of the equatorial ionosphere at dusk to penetration electric fields during intense magnetic storms

et al. 2007

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“…The complexity associated with the last two issues is beyond the scope of this paper. However, we intend to explore the impact of E×B motion on plasmasphere refilling with the self-consistent SAMI3/RCM (Rice Convection Model) code (Huba et al, 2005) in the near future. With the coupled model, future work will include (a) magnetospheric convection, which may limit saturation densities at these L-shells, (b) co-rotation, which would be necessary for accurate simulations at geosynchronous orbit and for comparisons to the relative wealth of data from that altitude (Sojka and Wrenn, 1985;Song et al, 1988;Singh and Horwitz, 1992;Su et al, 2001, and references therein), (c) consideration of the dependence of refilling on magnetospheric activity (see, e.g.…”

Section: Discussionmentioning

confidence: 99%

Simulation of field-aligned H<sup>+</sup> and He<sup>+</sup> dynamics during late-stage plasmasphere refilling

2008

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Abstract. The refilling of the plasmasphere for 3≤L≤4 following a model storm is simulated over long times (days) using the NRL ionosphere code SAMI2 (Sami2 is Another Model of the Ionosphere). Refilling is dependent on the supply of topside H + and He + ions with the result that H + refilling rates decrease and He + refilling rates generally increase with increasing F 10.7 index. Both early-and latestage refilling are affected by net ion flows from the warmer to the colder geomagnetic hemisphere. When these flows are strong, the ability of the "winter helium bulge" to increase He + refilling rates is suppressed. When neutral winds are not included, refilling rates fall, typically by a factor of two. In most cases, late-stage He + refilling is proportional to H + refilling, with typical He + /H + density ratios of 2% for solar minimum and 10% for solar maximum. For high values of F 10.7, He + refilling exhibits a strong diurnal variation so that the He + /H + density ratio varies by as much as a factor of two during late-stage refilling. Finally if the plasmasphere is left undisturbed, the H + density can refill for as long as five weeks at L=3 and ten weeks at L=4, with saturation densities nearly an order of magnitude greater than typical observed densities. This confirms that the plasmasphere at these L values rarely obtains saturation.

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“…A modified version of the NRL 3-D global ionosphere code SAMI3 (Huba et al, 2000(Huba et al, , 2005 was used for this purpose. This version of SAMI3 was recently applied to ESF studies (Huba et al, 2008;Krall et al, 2009) and models a "wedge" of the post-sunset ionosphere; it was limited to 4 • in longitude with a periodic boundary condition in order to obtain sufficient resolution for ESF modeling.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Equinoctial asymmetry of a low-latitude ionosphere-thermosphere system and equatorial irregularities: evidence for meridional wind control

et al. 2009

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Abstract. Nocturnal ionospheric height variations were analyzed along the meridian of 100 • E by using ionosonde data. Two ionosondes were installed near the magnetic conjugate points at low latitudes, and the third station was situated near the magnetic equator. Ionospheric virtual heights were scaled every 15 min and vertical E×B drift velocities were inferred from the equatorial station. By incorporating the inferred equatorial vertical drift velocity, ionospheric bottom heights with the absence of wind were modeled for the two low-latitude conjugate stations, and the deviation in heights from the model outputs was used to infer the transequatorial meridional thermospheric winds. The results obtained for the September and March equinoxes of years 2004 and 2005, respectively, were compared, and a significant difference in the meridional wind was found. An oscillation with a period of approximately 7 h of the meridional wind existed in both the equinoxes, but its amplitude was larger in September as compared to that in March. When the equatorial height reached the maximum level due to the evening enhancement of the zonal electric field, the transequatorial meridional wind velocity reached approximately 10 and 40 m/s for the March and September equinoxes, respectively. This asymmetry of the ionosphere-thermosphere system was found to be associated with the previously reported equinoctial asymmetry of equatorial ionospheric irregularities; the probability for equatorial irregularities to occur is higher in March as compared to that in September at the Indian to Western Pacific Correspondence to: T. Maruyama (tmaru@nict.go.jp) longitudes. Numerical simulations of plasma bubble developments were conducted by incorporating the transequatorial neutral wind effect, and the results showed that the growth time (e-folding time) of the bubble was halved when the wind velocity changed from 10 to 40 m/s.

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Simulation study of penetration electric field effects on the low‐ to mid‐latitude ionosphere

Cited by 101 publications

References 19 publications

Response of the equatorial ionosphere at dusk to penetration electric fields during intense magnetic storms

Response of the equatorial ionosphere at dusk to penetration electric fields during intense magnetic storms

Simulation of field-aligned H<sup>+</sup> and He<sup>+</sup> dynamics during late-stage plasmasphere refilling

Equinoctial asymmetry of a low-latitude ionosphere-thermosphere system and equatorial irregularities: evidence for meridional wind control

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Simulation study of penetration electric field effects on the low‐ to mid‐latitude ionosphere

Cited by 101 publications

References 19 publications

Response of the equatorial ionosphere at dusk to penetration electric fields during intense magnetic storms

Response of the equatorial ionosphere at dusk to penetration electric fields during intense magnetic storms

Simulation of field-aligned H&lt;sup&gt;+&lt;/sup&gt; and He&lt;sup&gt;+&lt;/sup&gt; dynamics during late-stage plasmasphere refilling

Equinoctial asymmetry of a low-latitude ionosphere-thermosphere system and equatorial irregularities: evidence for meridional wind control

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Simulation of field-aligned H<sup>+</sup> and He<sup>+</sup> dynamics during late-stage plasmasphere refilling