Studies of Radio-Wave Absorption Features at a Subauroral Latitude

1971 ◽  
Vol 49 (11) ◽  
pp. 1411-1418
Author(s):  
M. A. Abdu ◽  
E. L. Vogan
Keyword(s):  
Radio Wave ◽  
The South ◽  
Wave Absorption ◽  
The North ◽  
Noise Absorption ◽  
Radio Wave Absorption ◽  
Cosmic Noise ◽  
Absorption Features ◽  
Absorption Measurements

Cosmic noise absorption measurements at 30 MHz were made simultaneously on two antennas having different beam widths at London, Ontario(53 °N geomagnetic, L = 3.1), a subauroral zone station. The data show that absorption is caused by regions of ionization which exhibit marked spatial non-uniformity within the antenna beams, and which have horizontal extensions limited more toward the south than toward the north of the station. The measurements also indicate the presence of auroral ionization at all times of the day over London.

Interplanetary energetic ions and polar radio wave absorption

1989 ◽  
Vol 94 (A4) ◽  
pp. 3543 ◽  
Author(s):  
T. P. Armstrong ◽  
C. M. Laird ◽  
D. Venkatesan ◽  
S. Krishnaswamy ◽  
T. J. Rosenberg
Keyword(s):  
Radio Wave ◽  
Energetic Ions ◽  
Wave Absorption ◽  
Radio Wave Absorption

scholarly journals Multi beam observations of cosmic radio noise using a VHF radar with beam forming by a Butler matrix

2011 ◽  
Vol 9 ◽  
pp. 349-357 ◽  
Author(s):  
T. Renkwitz ◽  
W. Singer ◽  
R. Latteck ◽  
M. Rapp
Keyword(s):  
Middle Atmosphere ◽  
Beam Forming ◽  
Cosmic Radio ◽  
Radio Noise ◽  
Spatiotemporal Resolution ◽  
Vhf Radar ◽  
Butler Matrix ◽  
The North ◽  
Noise Absorption ◽  
Cosmic Noise

Abstract. The Leibniz-Institute of Atmospheric Physics (IAP) in Kühlungsborn started to install a new MST radar on the North-Norwegian island Andøya (69.30° N, 16.04° E) in 2009. The new Middle Atmosphere Alomar Radar System (MAARSY) replaces the previous ALWIN radar which has been successfully operated for more than 10 years. The MAARSY radar provides increased temporal and spatial resolution combined with a flexible sequential point-to-point steering of the radar beam. To increase the spatiotemporal resolution of the observations a 16-port Butler matrix has been built and implemented to the radar. In conjunction with 64 Yagi antennas of the former ALWIN antenna array the Butler matrix simultaneously provides 16 individual beams. The beam forming capability of the Butler matrix arrangement has been verified observing the galactic cosmic radio noise of the supernova remnant Cassiopeia A. Furthermore, this multi beam configuration has been used in passive experiments to estimate the cosmic noise absorption at 53.5 MHz during events of enhanced solar and geomagnetic activity as indicators for enhanced ionization at altitudes below 90 km. These observations are well correlated with simultaneous observations of corresponding beams of the co-located imaging riometer AIRIS (69.14° N, 16.02° E) at 38.2 MHz. In addition, enhanced cosmic noise absorption goes along with enhanced electron densities at altitudes below about 90 km as observed with the co-located Saura MF radar using differential absorption and differential phase measurements.

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