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Detection of conjugate photoelectrons at Millstone Hill

1970; American Geophysical Union; Volume: 75; Issue: 4 Linguagem: Inglês

10.1029/ja075i004p00807

2156-2202

J. V. Evans, Irvin Joseph Gastman,

Impact of Light on Environment and Health

Journal of Geophysical Research (1896-1977)Volume 75, Issue 4 p. 807-815 Detection of conjugate photoelectrons at Millstone Hill J. V. Evans, J. V. EvansSearch for more papers by this authorI. J. Gastman, I. J. GastmanSearch for more papers by this author J. V. Evans, J. V. EvansSearch for more papers by this authorI. J. Gastman, I. J. GastmanSearch for more papers by this author First published: 1 February 1970 https://doi.org/10.1029/JA075i004p00807Citations: 42AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Abstract Photoelectrons arriving in the F region from the conjugate point have been detected at Millstone Hill during the winter night, by means of Thomson scatter observations of the plasma lines that appear in the signal spectrum. During winter, when the solar zenith angle χc at the conjugate point is less than 100° throughout the night, the plasma lines are continuously present, provided that the local plasma frequency exceeds 4.0 MHz. For a few days in the spring the lines disappear for a period around midnight when χc≥106°. These observations confirm that photoelectrons can escape from one hemisphere into the other for L values as large as 3.2. The arriving flux appears to be too weak, however, to give rise to significant excitation of the 6300-A line of atomic oxygen (J. F. Noxon, personal communication), which suggests that direct excitation may not be the main cause of the large predawn enhancements seen elsewhere. References Barbier, D., Recherches sur la raie 6300 de la luminescence atmosphérique nocturne, Ann. Geophys., 15, 179–186, 1959. Carlson, H. C., Ionospheric heating by magnetic conjugate-point photoelectrons, J. Geophys. Res., 71, 195–199, 1966. Carlson, H. C., G. M. Weill, Solar cycle variation of conjugate photoelectron flux onset timing deduced from 6300 A and Te observations, Ann. Geophys., 23, 569–572, 1967. Carru, H., M. Petit, P. Waldteufel, Mesure de température électroniques et ioniques par diffusion incoherente, J. Atmos. Terr. Phys., 29, 351–366, 1967. Cole, K. D., The predawn enhancement of 6300 A airglow, Ann. Geophys., 21, 156–158, 1965. Duboin, M. L., G. Lejeune, M. Petit, G. M. Weill, Excitation of the oxygen lines and ionospheric heating by conjugate photoelectrons, J. Atmos. Terr. Phys., 30, 299–304, 1968. Evans, J. V., Midlatitude electron and ion temperatures at sunspot minimum, Planet. Space Sci., 15, 1557–1570, 1967. Evans, J. V., Sunrise behavior of the F layer at midlatitudes, J. Geophys. Res., 73, 3489–3504, 1968. Evans, J. V., Theory and practice of ionosphere study by Thomson scatter radar, Proc. IEEE, 57, 496–530, 1969. Evans, J. V., M. Loewenthal, Ionospheric backscatter observations, Planet. Space Sci., 12, 915–944, 1964. Evans, J. V., G. P. Mantas, Thermal structure of the temperate latitude ionosphere, J. Atmos. T. err. Phys., 30, 563–577, 1968. Fontheim, E. G., A. E. Beutler, A. F. Nagy, Theoretical calculations of the conjugate pre-dawn effects, Ann. Geophys., 24, 489–495, 1968. Fremouw, E. J., J. Petriceks, F. W. Perkins, Thomson scatter measurements of magnetic field effects on the Landau damping and excitation of plasma waves, Phys. Fluids, 12, 869–874, 1969. Hanson, W. B., Electron temperatures in the upper atmosphere, Space Res., 3, 282–302, 1963. Kwei, M. W., Presunrise effects due to conjugate region photoelectronsIonospheric Res. Rep. 301Pennsylvania State Univ, 1967. Nagy, A. F., E. G. Fonthelm, R. S. Stolarski, A. E. Beutler, Ionospheric electron temperature calculations including protonospheric and conjugate effects, J. Geophys. Res., 74, 4667– 4676, 1969. Nisbet, J. S., Photoelectron escape from the ionosphere, J. Atmos. Terr. Phys., 30, 1257–1278, 1968. Perkins, F. W., E. E. Salpeter, Enhancement of plasma density fluctuations by non-thermal electrons, Phys. Rev., 139A, 59–69, 1965. Perkins, F. W., E. E. Salpeter, K. O. Yngvesson, Incoherent scatter from plasma oscillations in the ionosphere, Phys. Rev. Lett., 14, 579–581, 1965. Rao, B. C., J. L. Donley, Photoelectron flux in the topside ionosphere measured by retarding potential analyzers, J. Geophys. Res., 74, 1715–1719, 1969. Yngvesson, K. O., F. W. Perkins, Radar Thomson scatter studies of photoelectrons in the ionosphere and Landau damping, J. Geophys. Res., 73, 97–110, 1968. Citing Literature Volume75, Issue4Space Physics1 February 1970Pages 807-815 ReferencesRelatedInformation