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High resolution bistatic HF radar observations of ULF waves in artificially generated backscatter
Author(s) -
Wright Darren M.,
Yeoman Timothy K.
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl900606
Subject(s) - ionosphere , radar , physics , geophysics , backscatter (email) , geology , bistatic radar , remote sensing , radar imaging , telecommunications , computer science , wireless
High resolution HF radar observations of ULF waves in the ionosphere are possible by artificially generating irregularities using the EISCAT heater at Tromsø, Norway. The line‐of‐sight velocities from the CUTLASS radars have been combined for the first time to form bistatic flow vectors during a ULF wave, generating ionospheric electric field measurements with a higher accuracy than ever previously recorded by any instrument. A high‐ m wave observed in the ionosphere exhibits a frequency which is a harmonic of that of a low‐ m field line resonance which is observed simultaneously in the ionosphere and at the ground. The high‐ m pulsation resembles a class of particle driven wave previously recorded on VHF radars. These results are consistent with recent HF radar observations of small scale waves possessing similar characteristics to field line resonances and with the theory that the low‐ m wave may be driving the high‐ m wave through a non‐linear Kelvin‐Helmholtz instability.