Auroral pulsations from atmospheric waves

Luhmann, J. G.

doi:10.1029/ja084ia08p04224

Cited by 23 publications

(3 citation statements)

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“…Result (2) indicates that even activities as small as 00 I K, I I-, can give rise to the conditions for pulsating precipitation of auroral electrons in the dawn sectors. This fact probably means that even a very small auroral expansion can produce energetic electrons in the magnetosphere near the midnight sector.…”

Section: Conclusion and Discussionmentioning

confidence: 92%

“…Even if some state in the magnetosphere. pulsating auroras originate from ionospheric proIn spite of their importance, pulsating auroras cesses (e.g., Deehr and Romick (1) and Luhmann have not been studied well enough, possibly be- (2)), modulation of precipitation in pulsating au-cause of the weakness in luminosity and the roras (e.g., Whalen et al references therein). Kvifte and Petersen (6) showed the occurrence probability of a pulsating aurora in a magnetic latitude range from 65 to 68" and at 75" on the basis of photometric data for the period 1967-1968 from Tromso and Spitzbergen.…”

Section: Introductionmentioning

confidence: 99%

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Statistics of pulsating auroras on the basis of all-sky TV data from five stations. I. Occurrence frequency

Oguti¹,

Kokubun²,

Hayashi³

et al. 1981

Can. J. Phys.

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The frequency of occurrence of pulsating auroras is statistically examined on the basis of all-sky TV data for 34 nights from five stations, in a range from 61.5 to 74.3" in geomagnetic latitude. The results are that: (I) occurrence probability of a pulsating aurora is 100% after 4 h in geomagnetic local time, (2) pulsating auroras occur in the morning hours along the auroral oval even when magnetic activity is as small as 00 5 K , 5 1, (3) pulsating auroras occur even in the evening when K,, increases to greater than 3-, (4) drift of pulsating auroras is westward in the evening while it is eastward in the morning hours. (5) the region ofpulsating auroras splits into two zones. 64 to 68' and 61 to 63' in geomagnetic latitude, after 4 h geomagnetic local time for K , from 20 to 3-, and the splitting also appears to exist for greater K , as evidenced by observation other than our auroral data. These results are discussed in relation to distributions of cold plasma irregularities and energetic electrons in the magnetosphere.On a fait une etude statistique de la frequence d'apparition des aurores pulsantes, sur la base des donnees TV plein ciel obtenues au cours de 34 nuits a cinq stations situees dans un intervalle de latitude geomagnetique allant de 61,5 B 71.3". Cette etude a donne les resultats suivants:(1) la probabilite d'apparition d'aurores pulsantes est 100% apres 4 h en temps geomagnetique local; (2) il se produit des aurores pulsantes durant les heures du matin le long de I'ovale auroral m2me lorsque I'activite magnetique est aussi faible que 00 5 K , 5 1; (3) il se produit des aurores pulsantes mime dans la soiree lorsque K , croit au delB de 3-; (4) la derive des aurores pulsantes se fait vers I'ouest le soir, alors qu'elle est vers I'est durant les heures du matin;(5) la region d'aurores pulsantes se separe en deux zones, 64 a 68" et 61 a 63" de latitude geomagnetique apres 4 h, temps geomagnetique local, pour K , entre 20 et 3-, et cette separation semble exister aussi pour des valeurs plus grandes de K,,, comme I'indiquent des observations autres que nos donnees aurorales. Ces resultats sont discutes en relation avec les distributions d'irregularites de plasma froid et d'electrons de haute energie dans la magnetosphkre.[Traduit par le journal]Can. J. Phys., 59, 1150 (1981) Introduction and that in the dawn auroral zone (5) indicates a A pulsating aurora is likely to be a visible primary importance of pulsating precipitation of manifestation of the pulsating precipitation of energetic electrons in pulsating auroras. Hence, magnetospheric electrons, and the pulsating pre-the study of the pulsating aurora can have an cipitation could be the result of wave-particle essential importance in understanding the plasma interactions in the magnetosphere. Even if some state in the magnetosphere. pulsating auroras originate from ionospheric proIn spite of their importance, pulsating auroras cesses (e.g., Deehr and Romick (1) and Luhmann have not been studied well enough, possibly be-(2)), modulation of precipit...

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Section: Conclusion and Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Statistics of pulsating auroras on the basis of all-sky TV data from five stations. I. Occurrence frequency

Oguti¹,

Kokubun²,

Hayashi³

et al. 1981

Can. J. Phys.

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“…Novikov et al (1994) were the ®rst to point out, that a structured VLF emissions are connected with fast moving auroral patches. Luhmann (1979) proposed the generation of auroral pulsation from atmospheric waves. Stenbaek-Nielsen (1980) pointed that the ionospheric parameters have to be taken into account when studying the auroral pulsation generation.…”

Section: Introductionmentioning

confidence: 99%

Auroral pulsations and accompanying VLF emissions

et al. 1999

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Abstract. Results of simultaneous TV observations of pulsating auroral patches and ELF-VLF-emissions in the morning sector carried out in SodankylaÈ (Finland) on February 15, 1991 are presented. Auroral pulsating activity was typical having pulsating patches with characteristic periods of about 7 s. Narrow-band hiss emissions and chorus elements at intervals of 0.3±0.4 s formed the main ELF-VLF activity in the frequency range 1.0±2.5 kHz at the same time. The analysis of auroral images with time resolution of 0.04 s allowed perfectly separate analysis of spatial and temporal variations in the auroral luminosity. Mutual correspondence between the behaviour of the luminous auroral patches and the appearance of ELF noise type hiss emissions and VLF chorus trains was found in two intervals chosen for analysis. While the hiss emissions were associated with the appearance of luminosity inside a limited area close to the zenith, the structured VLF emissions were accompanied by rapid motion of luminosity inside the area. The spatial dimension of the pulsating area was about 45±50 km and luminosity propagated inside it with velocity of about 10±12 kms. We discuss a new approach to explain the 5±15 s auroral pulsation based on the theory of¯owing cyclotron maser and relaxation characteristics of ionosphere.

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Temporal characteristics and energy deposition of pulsating auroral patches

et al. 2016

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We present a careful statistical analysis of pulsating aurora (PA) using all‐sky green line (557.7 nm) images obtained at 3.3 Hz. Six well‐defined individual PA patches are identified and extracted using a contouring technique. Quantitative parameters such as the patch duration (on‐time and off‐time), peak intensity, and integrated intensity are determined for each patch and each pulsation. The resulting characteristics serve as strict observational constraints that any of the many competing theories attempting to explain PA must predict. The purpose of this paper is to determine the characteristics of PA patches in order to provide better observational constraints on the suggested mechanisms. All aspects of the temporal behavior of the individual patches appear to be erratic. Historically, PA has been defined very loosely and we argue that the use of the term “pulsating” is inappropriate since our findings and other published results are not regularly periodic and thus a more appropriate term may be fluctuating aurora. Further, we find that the observational constraints do not fit well with the flow cyclotron maser theory, which in particular is suggested to create PA patches. There is no clear candidate of the suggested mechanisms and drivers to explain the observational constraints set by the PA patches in a satisfactory manner.

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Auroral pulsations from atmospheric waves

Cited by 23 publications

References 32 publications

Statistics of pulsating auroras on the basis of all-sky TV data from five stations. I. Occurrence frequency

Statistics of pulsating auroras on the basis of all-sky TV data from five stations. I. Occurrence frequency

Auroral pulsations and accompanying VLF emissions

Temporal characteristics and energy deposition of pulsating auroral patches

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