- Open Access
Drift motion of ionospheric arc-like absorption regions observed with a 256-beam imaging riometer in Alaska
Earth, Planets and Space volume 53, pages753–760(2001)
We studied the local time dependence of the direction of cosmic noise absorption drift using a large data set obtained with a 16 × 16-antenna imaging riometer in Poker Flat, Alaska (65.1°N, 147.5° W in geographic coordinates; 65.4°N, 100.7° in geomagnetic coordinates). The drift velocities were determined using regression lines for the absorption peaks, which were automatically detected. Based on the characteristics of the motion of the drift region, the events were categorized into three magnetic local time (MLT) groups: I (13–19 MLT), II (21-01 MLT) and III (01–07 MLT). Most events in group I move southwestward with steady velocities. Events in group II had various velocities and directions. Events in group III also had various velocities, but the tilt angles of their vector velocities from the eastward axis were between −90° and 90°, meaning that they moved eastward. These results are consistent with some found in previous studies. A polar plot of the drift had a pattern with features similar to that of magnetospheric convection, which has been reported on several studies: equatorward in the pre-midnight sector and sunward in the morning and evening sectors.
Akasofu, S.-I., Auroral arcs and auroral potential structure, in Physics of Auroral Arc Formation, edited by S.-I. Akasofu and J. R. Kan, pp. 1–14, American Geophysical Union, Washington, D.C., 1981.
Berkey, F. T., V. M. Driatskiy, K. Henriksen, B. Hultqvist, D. H. Jelly, T. I. Shchuka, A. Theander, and J. Yliniemi, A synoptic investigation of particle precipitation dynamics for 60 substorms in IQSY (1964–1965) and IASY(1969), Planet. Space Sci., 22, 255–307, 1974.
Butler, J. and R. Lowe, Beam-forming matrix simplifies design of electronically scanned antennas, Electron. Des., 12, 170–173, 1961.
Hargreaves, J. K., Auroral motions observed with riometers: Movements between stations widely separated in longitude, J. Atmos. Terr. Phys., 29, 1159–1164, 1967.
Hargreaves, J. K., Conjugate and closely-spaced observations of auroral radio absorption—IV The movement of simple features, Planet. Space Sci., 18, 1691–1705, 1970.
Jelly, D. H., On the morphology of auroral absorption during substorms, Can. J. Phys., 48, 335–345, 1970.
Kainuma, S., Y. Murayama, H. Mori, and K. Igarashi, Development of 256-beam Imaging Riometer, Trans. IEICE, B-II, J79-B-II, 7, 422–425, 1996.
Kikuchi, T. and H. Yamagishi, Drift of auroral absorption observed with a scanning beam riometer at Syowa station, J. Commun. Res. Lab., 37, 1–14, March 1990.
Kikuchi, T., H. Yamagishi, and M. Lester, Drift of auroral absorption due to the magnetospheric convection observed with the scanning narrow beam riometer during Sundial-86, Annales Geophys., 8, 431–439, 1990.
Murayama, Y., H. Mori, S. Kainuma, M. Ishii, I. Nishimuta, K. Igarashi, H. Yamagishi, and M. Nishino, Development of a high-resolution imaging riometer for the middle and atmosphere observation program at Poker Flat, Alaska, J. Atmos. Terr. Phys., 59, 8, 925–937, 1997.
Nishida, A., Coherence of geomagnetic DP2 magnetic fluctuations with interplanetary magnetic variations, J. Geophys. Res., 73, 5549–5559, 1968.
Nishida, A., Geomagnetic diagnosis ofthe magnetosphere, Springer-Verlag, New York, 1978.
Oguti, T., TV observations of auroral arcs, in Physics of Auroral Arc Formation, edited by S.-I. Akasofu and J. R. Kan, pp. 31–41, American Geophysical Union, Washington, D.C., 1981.
Olson, J. V., G. Rostoker, and G. Olchowy, A study of concurrent riometer and magnetometer variations in the Pc 4–5 pulsation band, J. Geophys. Res., 85, 1695–1702, 1980.
Pudovkin, M. I., O. I. Shumilov, and S. A. Zaitzeva, Dynamics of the zone of corpuscular precipitations, Planet. Space Sci., 16, 881–890, 1968.
Stoker, P. H., M. J. Mathews, and M. W. J. Scourfield, Coordinated measurements of auroral light intensities and riometric radio-wave absorption, Geophys. Res. Lett., 23, 641–644, 1996.
Stoker, P. H., M. J. Mathews, and M. W. J. Scourfield, Cosmic radio noise absorption related to structures in auroral luminosity, J. Geophys. Res., 102, 7439–7447, 1997.
Theander, A., Studies ofauroral absorption substorms, Ph.D. Thesis, Kiruna Geophysical Observatory, Report No. 723, 1972.
About this article
Cite this article
Kainuma, S., Ishii, M., Murayama, Y. et al. Drift motion of ionospheric arc-like absorption regions observed with a 256-beam imaging riometer in Alaska. Earth Planet Sp 53, 753–760 (2001) doi:10.1186/BF03352403
- Tilt Angle
- Drift Velocity
- Magnetic Local Time
- Meridional Component
- Evening Sector