Multispectral tomographic imaging of the midlatitude aurora

Semeter, J. L.; Mendillo, M.; Baumgardner, Jeffrey

doi:10.1029/1999ja900305

Cited by 25 publications

(33 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The directly measured quantity is a line-ofsight integral through the emitting region, several of which are depicted in Figure 1a. Access to the intrinsic volumetric quantity (photon volume emission rate) requires the use of tomographic techniques using multistation observations [Frey et al, 1996;Semeter et al, 1999]. More commonly, the integrated intensities are analyzed directly [Rees and Luckey, 1974;Hecht et al, 1989;Strickland et al, 1994;Zettergren et al, 2007].…”

Section: Overview Of the Forward Problemmentioning

confidence: 99%

Model‐Based Inversion of Auroral Processes

Semeter

Zettergren

2014

Modeling the Ionosphere–Thermosphere System

Self Cite

View full text Add to dashboard Cite

Section: Overview Of the Forward Problemmentioning

confidence: 99%

Model‐Based Inversion of Auroral Processes

Semeter

Zettergren

2014

Modeling the Ionosphere–Thermosphere System

Self Cite

View full text Add to dashboard Cite

“…Additional comparisons made locally are possible since observations using a Boston University all-sky camera at Millstone Hill date to the SAR arc recorded on the night of 13 November 1983 (∼50 R above background). The SAR arc of 22 March 1990 studied by Foster et al (1994) was ∼100 R above background, as was the event of 5 March 1995 analyzed tomographically by Semeter et al (1999). As shown in Fig.…”

Section: Previous Sar Arc Brightnessesmentioning

confidence: 86%

“…Moreover, those studied occurred prior to the use of incoherent scatter radar (ISR) diagnostics to specify the ionospheric state parameters within a SAR arc, and prior to the use of in-situ satellite data to describe the signatures of particles and fields of magnetospheric origin upon the topside ionosphere. When such observations became available at Millstone Hill (Mendillo et al, 1987;Foster et al, 1994;Semeter et al, 1999), the SAR arc events observed were at the extremely faint end of brightness values (∼50 R to ∼few 100 R). These events offered challenges, as pointed out by Kozyra et al (1997), since the observed ionospheric electron temperatures appeared to be insufficient to account for such low brightness SAR arcs.…”

Section: Discussionmentioning

confidence: 99%

“…Using the measured electric field of 30 mV/m (Fig. 8) and a typical SAR arc emission altitude of 350 km (Semeter et al, 1999), we find that T e =400 K. To become a significant source of O( 1 D), the electron gas must have a significant density in the high energy tail above 1.96 eV (the excitation potential). This requires T e >3000 K (Rees and Roble, 1975), or E>85 mV/m.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

A very bright SAR arc: implications for extreme magnetosphere-ionosphere coupling

et al. 2007

View full text Add to dashboard Cite

Abstract. In contrast to the polar aurora visible during geomagnetic storms, stable auroral red (SAR) arcs offer a subvisual manifestation of direct magnetosphere-ionosphere (M-I) coupling at midlatitudes. The SAR arc emission at 6300Å is driven by field-aligned magnetospheric energy transport from ring current/plasmapause locations into the ionosphere-thermosphere system. The first SAR arc was observed at the dawn of the space age (1956), and the typical brightness levels and occurrence patterns obtained from subsequent decades of observations appear to be consistent with the downward heat conduction theory, i.e., heated ambient Flayer electrons excite oxygen atoms to produce a spectrally pure emission. On very rare occasions, a SAR arc has been reported to be at brightness levels visible to the naked eye. Here we report on the first case of a very bright SAR arc (∼13 kilo-Rayleighs) observed by four diagnostic systems that sampled various aspects of the sub-auroral domain near Millstone Hill, MA, on the night of 29 October 1991: an imaging spectrograph, an all-sky camera, an incoherent scatter radar (ISR), and a DMSP satellite. Simulations of emission using the ISR and DMSP data with the MSIS neutral atmosphere succeed in reproducing the brightness levels observed. This provides a robust confirmation of M-I coupling theory in its most extreme aeronomic form within the innermost magnetosphere (L∼2) during a rare superstorm event. The unusually high brightness value appears to be due to the rare occurrence of the heating of dense ionospheric plasma just equatorward of the trough/plasmapause location, in contrast to the more typical heating of the less dense F-layer within the trough.

show abstract

“…Frey et al (1998) estimated some parameters of conductivity distributions by simultaneous electron density and spectral measurements made by the EISCAT radar and three CCD cameras. Some luminosity properties in the emissions of 557.7 and 630.0 nm for the Polar Cap arcs and mid-latitude auroras are investigated in the papers by Doe et al (1997) and Semeter et al (1999) by using the tomographic approach.…”

Section: Introductionmentioning

confidence: 99%

Features of stable diffuse arcs observed by means of auroral tomography

2007

View full text Add to dashboard Cite

Abstract. In this paper we study the spatial distribution of optical volume emission rates and peculiarities of the luminosity intensity within weak diffuse auroral arcs recovered by means of auroral tomography. The tomographic images are obtained from sets of scanning multi-channel photometer data obtained in February 1999 on the Kola Peninsula in Russia at three sites of a chain extending 226 km along the geomagnetic meridian. The 427.8-and 557.7-nm emissions of a 15-s time resolution observed within one hour during low geomagnetic activity are analyzed. We found that the intensity profile of an individual arc along the geomagnetic meridian has an inverted-V-shape. The luminosity maximum altitude decrease by 4-14 km at about 140 km distance in the south-north direction can be observed during two or more diffuse arcs. The parameters of the precipitating electron flux are obtained from an integral equation, which determines the best relationship between the 427.8-nm intensity height profile and an arbitrary particle energy spectrum. A dimensionless function of the energy dissipation is used as the core in the integral equation. The estimated average energy of electron flux, which generated the isolated diffuse arc, is 1-2 keV higher in the central part of the arc in comparison to values at its borders.

show abstract

Multispectral tomographic imaging of the midlatitude aurora

Cited by 25 publications

References 31 publications

Model‐Based Inversion of Auroral Processes

Model‐Based Inversion of Auroral Processes

A very bright SAR arc: implications for extreme magnetosphere-ionosphere coupling

Features of stable diffuse arcs observed by means of auroral tomography

Contact Info

Product

Resources

About