Some observations of short-duration cosmic noise absorption events in nearly conjugate regions at high magnetic latitude

Eriksen, K.W.; Gillmor, C. Stewart; Hargreaves, J. K.

doi:10.1016/0021-9169(64)90110-2

Cited by 15 publications

(7 citation statements)

References 4 publications

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“…At the South Pole (geomagnetic latitude 78.6 ~ S, L= 13) the AA occurrence frequency has the main maximum in the hours before magnetic midnight and another one before magnetic noon . At Mirnyy (geomagnetic latitude 77,0 ~ S, L= 19) the occurrence frequency maximum has been found to occur close to geomagnetic midnight (ERIKSEN et al, 1964).…”

Section: Diurnal Variationsmentioning

confidence: 99%

“…The absorption is higher at the point which has winter, so the ratio of the absorption values at the two points varies with time as a sine wave. Not only the intensity of the AA events have been found to be greater in winter but also the occurrence frequency (ERIKSEN et aL, 1964). The single-ended events, i.e.…”

Section: Seasonal Variationmentioning

confidence: 99%

“…The single-ended events, i.e. AA events which occur at only one end of a geomagnetic field line, occur mainly at the end where there is local winter (ERIKSEN et al, 1964).…”

Section: Seasonal Variationmentioning

confidence: 99%

“…The magnitude of the absorption is greater at the end of the field line being in the winter hemisphere than at the one in the summer hemisphere even under similar illumination conditions. Also the number of events show this relation (LEINBACH and BASLER, 1963;MATHER and WESCOTT, 1963;ERIKSEN et al, 1964;LITTLE et al, 1965;HARGREAVES and CHIVERS, 1965). There are events exclusively confined to one hemisphere.…”

Section: Geographical Distributionmentioning

confidence: 99%

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Ionospheric absorption of cosmic radio noise

Hultqvist¹

1966

Space Sci Rev

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The development of the field of study of ionospheric absorption of cosmic radio noise since 1962 is reviewed. Contributions to the basic theory and methods of analysis are first dealt with. News concerning measuring technique are then briefly treated. In the main part of the paper the development of our knowledge of sudden cosmic noise absorption, polar cap absorption, and auroral absorption is reviewed. The emphasis is on the ionospheric effects. The solar disturbances associated with the absorption effects, the propagation of particles from the Sun to the Earth, and other extraterrestrial sides of the story are not treated.

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Section: Diurnal Variationsmentioning

confidence: 99%

Section: Seasonal Variationmentioning

confidence: 99%

“…The single-ended events, i.e. AA events which occur at only one end of a geomagnetic field line, occur mainly at the end where there is local winter (ERIKSEN et al, 1964).…”

Section: Seasonal Variationmentioning

confidence: 99%

Section: Geographical Distributionmentioning

confidence: 99%

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Ionospheric absorption of cosmic radio noise

Hultqvist¹

1966

Space Sci Rev

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“…Other aspects of the ITSA work in this field have been, and are being, published. elsewhere (e.g., Eriksen, Gillmor, and Hargreaves, 1964;Hargreaves and Cowley, 1967) and the first object of these studies has been to establish empirically the essential conjugate properties of auroral radio absorption to provide a guide and a test for theoretical ideas about the aurora and the magnetosphere. The emphasis is on auroral absorption as such, and relations with other auroral phenomena are not considered in the present work.…”

Section: Introductionmentioning

confidence: 99%

Correlation of Auroral Radio Absorption Between Conjugate Points

Hargreaves

Ecklund

1968

Radio Science

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Observations with riometers at four pairs of conjugate, or nearly conjugate, stations have been studied to determine how closely auroral radio absorption is correlated at magnetically conjugate points. The available evidence suggests that, if the loss of correlation due to imperfect siting of the stations and to the movement of conjugate points is taken into account, the conjugate correlation remains suprisingly good to high latitudes and perhaps throughout the auroral region. It is suggested that conjugate points move seasonally and irregularly by 100 to 200 km at the earth's surface.

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U.S.A. National Committee Report, Fifteenth URSI General Assembly, Munich, September 1966: Commission 3, Ionospheric Radio; Progress in Ionospheric Radio

Bowhill¹,

Bibl²,

Calvert³

et al. 1966

Radio Science

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Auroral absorption measured in the auroral zone with riometers is on the average more pronounced in the winter months for both hemispheres. Also, in winter it has a pronounced diurnal variation with a maximum a few hours before noon. The average absorption in winter is twice that in summer, but sunlight has no influence in its value [Leinbach and Basler, 1963; Basler, 1963]. Individual events at night are characterized by a quiet phase of relatively small absorption, a sharp increase of absorption associated with the breakup phase of the visible aurora, and a fast recovery with irregular fluctuation of absorption. Detailed correlation of areas of absorption and luminosity exists for such events [Ansari, 1964]. The structure is less than 200 km in the north‐south direction and 700 km in the east‐west direction [Parthasarathy and Berkey, 1965]. An event seen only after midnight consists of a relatively slow increase and recovery of extremely high absorption with no de~ailed correlation of light emission and absorption. It is associated with a harder electron spectrum [Ansari, 1964]. A peculiar type of absorption event frequently observed during midmorning usually increases very smoothly, reaches a high value of absorption, and is not accompanied by appreciable magnetic activity [Ansari, 1965]. Absorption associated either with negative bays or with breakup events shows no difference in intensity between day and night [Brown and Barcus, 1963; Brown, 1964]. There is a limited correlation between the high‐energy part of the electron spectrum, as measured by X‐rays in balloons, and the absorption [Barcus, 1965].

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Some observations of short-duration cosmic noise absorption events in nearly conjugate regions at high magnetic latitude

Cited by 15 publications

References 4 publications

Ionospheric absorption of cosmic radio noise

Ionospheric absorption of cosmic radio noise

Correlation of Auroral Radio Absorption Between Conjugate Points

U.S.A. National Committee Report, Fifteenth URSI General Assembly, Munich, September 1966: Commission 3, Ionospheric Radio; Progress in Ionospheric Radio

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