A study of the Joule and Lorentz inputs in the production of atmospheric gravity waves in the upper thermosphere

Moffett, R. J.; Millward, G. H.

doi:10.1007/s00585-997-0779-6

Cited by 15 publications

(8 citation statements)

References 19 publications

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“…Since it is an appropriately exponential function of height, L / J is also approximately constant with heights above around 120 km. This is consistent with other results [ Balthazor et al , 1997].…”

Section: Discussionsupporting

confidence: 94%

Statistical height‐dependent relative importance of the Lorentz force and Joule heating in generating atmospheric gravity waves in the auroral electrojets

Yuan¹,

Fujii²,

Nozawa³

et al. 2005

J. Geophys. Res.

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On the basis of 28 days of European Incoherent Scatter Common Program 1 mode data obtained between 1989 and 1991, we have determined statistical ratios of the Lorentz force (L) to the Joule heating rate terms (J) in generating atmospheric gravity waves in the auroral electrojets between 101 and 125 km altitudes. Under the altitude of 120 km the ratio (L/J) rapidly decreases with increasing height, indicating that the relative importance of the two sources is very critically dependent on altitude. Above this altitude, L/J is approximately constant with height. We have also derived a transition height of about 116 km. Under this height the Lorentz force is relatively important. Above this height, Joule heating dominates. Considering the effect of the neutral wind, relative deviations caused by the neutral wind are estimated at less than 10% between 101 and 125 km altitudes. Therefore we can ignore the effect of neutral wind on the ratio. In order to fulfill the demand, in practice, a statistical curve of the ratio with height has been provided.

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Section: Discussionsupporting

confidence: 94%

Statistical height‐dependent relative importance of the Lorentz force and Joule heating in generating atmospheric gravity waves in the auroral electrojets

Yuan¹,

Fujii²,

Nozawa³

et al. 2005

J. Geophys. Res.

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“…Figure 7 shows that the waves with the largest amplitudes originate at very high latitudes, most clearly in the Northern Hemisphere. TADs are generally assumed to be gravity waves propagating away from a region in which Joule heating occurs [Richmond, 1978;Balthazor et al, 1997]. In our study, we use the TADs as a marker of the source region in which the neutrals are Joule heated.…”

Section: 1002/2013ja019297mentioning

confidence: 99%

Energy coupling during the August 2011 magnetic storm

Huang

Sutton

et al. 2014

JGR Space Physics

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We present results from an analysis of high-latitude ionosphere-thermosphere (IT) coupling to the solar wind during a moderate magnetic storm which occurred on 5-6 August 2011. During the storm, a multipoint set of observations of the ionosphere and thermosphere was available. We make use of ionospheric measurements of electromagnetic and particle energy made by the Defense Meteorological Satellite Program and neutral densities measured by the Gravity Recovery and Climate Experiment satellite to infer (1) the energy budget and (2) timing of the energy transfer process during the storm. We conclude that the primary location for energy input to the IT system may be the extremely high latitude region. We suggest that the total energy available to the IT system is not completely captured either by observation or empirical models.

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“…Appearance of maxima in the neutral densities derived from accelerometer measurements on the CHAMP and GRACE satellites has generally been accepted as evidence of localized heating below the satellite altitude. However, maxima can also be created by gravity wave-like perturbations in the form of traveling atmospheric disturbances (TADs), which propagate away from the region where heating occurs (Balthazor et al, 1997;Bruinsma & Forbes, 2007;Lu et al, 2016;Richmond, 1978) or transport of heated neutrals away from the region where they are actually heated (Killeen et al, 1987). This ambiguity in interpretation of the neutral mass density maxima is examined in detail in section 5 below.…”

Section: Introductionmentioning

confidence: 99%

High‐Latitude Neutral Mass Density Maxima

Huang

et al. 2017

JGR Space Physics

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Recent studies have reported that thermospheric effects due to solar wind driving can be observed poleward of auroral latitudes. In these papers, the measured neutral mass density perturbations appear as narrow, localized maxima in the cusp and polar cap. They conclude that Joule heating below the spacecraft is the cause of the mass density increases, which are sometimes associated with local field‐aligned current structures, but not always. In this paper we investigate neutral mass densities measured by accelerometers on the CHAllenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) spacecraft from launch until years 2010 (CHAMP) and 2012 (GRACE), approximately 10 years of observations from each satellite. We extract local maxima in neutral mass densities over the background using a smoothing window with size of one quarter of the orbit. The maxima have been analyzed for each year and also for the duration of each set of satellite observations. We show where they occur, under what solar wind conditions, and their relation to magnetic activity. The region with the highest frequency of occurrence coincides approximately with the cusp and mantle, with little direct evidence of an auroral zone source. Our conclusions agree with the “hot polar cap” observations that have been reported and studied in the past.

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A study of the Joule and Lorentz inputs in the production of atmospheric gravity waves in the upper thermosphere

Cited by 15 publications

References 19 publications

Statistical height‐dependent relative importance of the Lorentz force and Joule heating in generating atmospheric gravity waves in the auroral electrojets

Statistical height‐dependent relative importance of the Lorentz force and Joule heating in generating atmospheric gravity waves in the auroral electrojets

Energy coupling during the August 2011 magnetic storm

High‐Latitude Neutral Mass Density Maxima

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