The Sheffield University plasmasphere ionosphere model—a review

Bailey, G. J.; Balan, N.; Su, Yi

doi:10.1016/s1364-6826(96)00155-1

Cited by 152 publications

(142 citation statements)

References 37 publications

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“…Outputs include the plasma temperatures, concentrations and field-aligned fluxes. A full description of the model and its evolution have been given by Bailey and Sellek (1990), Bailey and Balan (1996) and Bailey et al (1997).…”

Section: Preliminary Model Resultsmentioning

confidence: 99%

He<sup>+</sup> dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results

et al. 2002

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Abstract.Observations made by the DMSP F10 satellite during the recovery phase from geomagnetic disturbances in June 1991 show regions of He + dominance around 830 km altitude at 09:00 MLT. These regions are co-located with a trough in ionisation observed around 55 • in the winter hemisphere. Plasma temperature and concentration observations made during the severe geomagnetic storm of 24 March 1991 are used as a case study to determine the effects of geomagnetic disturbances along the orbit of the F10 satellite. Previous explanations for He + dominance in this trough region relate to the part of the respective flux tubes that is in darkness. Such conditions are not relevant for this study, since the whole of the respective flux tubes are sunlit. A new mechanism is proposed to explain the He + dominance in the trough region. This mechanism is based on plasma transport and chemical reaction effects in the F-region and topside ionosphere, and on the time scales for such chemical reactions. Flux tubes previously depleted by geomagnetic storm effects refill during the recovery phase from the ionosphere as a result of pressure differences along the flux tubes. Following a geomagnetic disturbance, the He + ion recovers quickly via the rapid photoionisation of neutral helium, in the F-region and the topside. The recovery of the O + and H + ions is less rapid. This is proposed as a result of the respective charge exchange reactions with neutral atomic hydrogen and oxygen. Preliminary model calculations support the proposed mechanism.

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Section: Preliminary Model Resultsmentioning

confidence: 99%

He<sup>+</sup> dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results

et al. 2002

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“…The model used for the present study is SUPIM, the She eld University Plasmasphere Ionosphere Model (Bailey and Sellek, 1990;Bailey et al, 1993Bailey et al, , 1997). In the model, coupled time-dependent equations of continuity, momentum and energy balance for the O , H , He , N 2 , O 2 and NO ions and the electrons are solved along closed magnetic ®eld lines for the ion and electron densities, ®eld-aligned velocities and temperatures.…”

Section: Model Calculations and Resultsmentioning

confidence: 99%

“…This result is contrary to expectations, since the di erence in the solar EUV¯ux between the December and June solstices, due to the changes in the Sun-Earth distance, is only about 6%. Suggested source mechanisms for the annual and seasonal variations in the topside ionosphere at low latitudes are investigated by using SUPIM (She eld University plasmasphere ionosphere model) (Bailey and Sellek, 1990;Bailey et al, 1993Bailey et al, , 1997.…”

Section: Introductionmentioning

confidence: 99%

Annual and seasonal variations in the low-latitude topside ionosphere

Bailey

Oyama

1998

Ann Geophysicae

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Abstract. Annual and seasonal variations in the lowlatitude topside ionosphere are investigated using observations made by the Hinotori satellite and the She eld University Plasmasphere Ionosphere Model (SUPIM). The observed electron densities at 600 km altitude show a strong annual anomaly at all longitudes. The average electron densities of conjugate latitudes within the latitude range AE25 are higher at the December solstice than at the June solstice by about 100% during daytime and 30% during night-time. Model calculations show that the annual variations in the neutral gas densities play important roles. The model values obtained from calculations with inputs for the neutral densities obtained from MSIS86 reproduce the general behaviour of the observed annual anomaly. However, the di erences in the modelled electron densities at the two solstices are only about 30% of that seen in the observed values. The model calculations suggest that while the di erences between the solstice values of neutral wind, resulting from the coupling of the neutral gas and plasma, may also make a signi®cant contribution to the daytime annual anomaly, the E Â B drift velocity may slightly weaken the annual anomaly during daytime and strengthen the anomaly during the post-sunset period. It is suggested that energy sources, other than those arising from the 6% di erence in the solar EUV¯uxes at the two solstices due to the change in the Sun-Earth distance, may contribute to the annual anomaly. Observations show strong seasonal variations at the solstices, with the electron density at 600 km altitude being higher in the summer hemisphere than in the winter hemisphere, contrary to the behaviour in NmF2. Model calculations con®rm that the seasonal behaviour results from e ects caused by transequatorial component of the neutral wind in the direction summer hemisphere to winter hemisphere.

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“…The magnitude and structure of the ion density enhancement and electric field can be modified in the model. Large scale background winds in these simulations have been provided by the 3-D CTIP (Coupled Thermosphere Ionosphere Plasmasphere) lower resolution global model (Bailey et al, 1997;Fuller-Rowell et al, 1987). The CTIP model simulates the effects of different propagating diurnal and semidiurnal tides, assumed to propagate up from the troposphere and stratosphere into the thermosphere.…”

Section: Modelmentioning

confidence: 99%

Sensitivity studies of the E region neutral response to the postmidnight diffuse aurora

Parish

Lyons

2006

Ann. Geophys.

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Abstract. Measurements of the neutral thermosphere within the postmidnight substorm recovery phase diffuse aurora show very large horizontal winds, and strong vertical structure. Rocket, satellite, and ground based observations during the ARIA (Atmospheric Response in Aurora) campaigns, and earlier dawn side rocket observations, indicate neutral winds of up to 200 m/s, and a characteristic jet-like wind maximum around 110 to 120-km altitude, with strong shears above and below. The observed wind magnitudes are found to have a dependence on geomagnetic activity level, but recent modeling studies suggest that tides which propagate up from the troposphere and stratosphere may play an important role in generating the strong vertical variations in the neutral winds. The relative importance of auroral and tidal forcing in producing the measured wind structure is not known, however. Simulations have been performed using a three dimensional (3-D) high resolution limited area thermosphere model to understand the processes which generate the observed neutral structure within the postmidnight diffuse aurora. Parameters measured during the ARIA I observational campaign have been used to provide auroral forcing inputs for the model. Global background winds and tides have been provided by the CTIP (Coupled Thermosphere Ionosphere Plasmasphere) model. The sensitivity of the response of the neutral atmosphere to changes in different parameters has been examined. Variations in the amplitudes and phases of the propagating tides in the background winds are found to have significant effects on the neutral structure in the E region, and the wind structure below around 110 km is found to be mainly produced by tidal forcing. Changes in the electric field and ion density affect the winds above around 120 km, and the importance of auroral forcing is found to depend on background winds. Variations in the orientation of the aurora relative to the background field, which may be Correspondence to: H. F. Parish (helen@atmos.ucla.edu) caused by changes in the interplanetary magnetic field, are also found to modify the wind structure. When both auroral forcing and propagating tides are included, many of the basic characteristics of the wind structure are displayed, although the great strength of the wind shears is not well reproduced. The strength of the shears may be related to a currently unmodeled process, or to different types of waves.

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The Sheffield University plasmasphere ionosphere model—a review

Cited by 152 publications

References 37 publications

He<sup>+</sup> dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results

He<sup>+</sup> dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results

Annual and seasonal variations in the low-latitude topside ionosphere

Sensitivity studies of the E region neutral response to the postmidnight diffuse aurora

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The Sheffield University plasmasphere ionosphere model—a review

Cited by 152 publications

References 37 publications

He&lt;sup&gt;+&lt;/sup&gt; dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results

He&lt;sup&gt;+&lt;/sup&gt; dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results

Annual and seasonal variations in the low-latitude topside ionosphere

Sensitivity studies of the E region neutral response to the postmidnight diffuse aurora

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He<sup>+</sup> dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results

He<sup>+</sup> dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results