scholarly journals Hodograph method to estimate the latitudinal profile of the field-line resonance frequency using the data from two ground magnetometers

2013 ◽  
Vol 65 (5) ◽  
pp. 435-446
Author(s):  
V. A. Pilipenko ◽  
H. Kawano ◽  
I. R. Mann
Keyword(s):  
Resonance Frequency ◽  
Field Line ◽  
Field Line Resonance ◽  
Hodograph Method ◽  
Line Resonance ◽  
Latitudinal Profile

scholarly journals Observations of Pc 3-4 and Pi 2 geomagnetic pulsations in the low-latitude ionosphere

1999 ◽  
Vol 17 (11) ◽  
pp. 1397-1410 ◽  
Author(s):  
R. A. Marshall ◽  
F. W. Menk
Keyword(s):  
Resonance Frequency ◽  
Field Line ◽  
Night Time ◽  
Field Line Resonance ◽  
Radio Science ◽  
Ionospheric Physics ◽  
Line Resonance ◽  
Frequency Independent ◽  
Radio Signals ◽  
Magnetic Pulsations

Abstract. Day-time Pc 3–4 (~5–60 mHz) and night-time Pi 2 (~5–20 mHz) ULF waves propagating down through the ionosphere can cause oscillations in the Doppler shift of HF radio transmissions that are correlated with the magnetic pulsations recorded on the ground. In order to examine properties of these correlated signals, we conducted a joint HF Doppler/magnetometer experiment for two six-month intervals at a location near L = 1.8. The magnetic pulsations were best correlated with ionospheric oscillations from near the F region peak. The Doppler oscillations were in phase at two different altitudes, and their amplitude increased in proportion to the radio sounding frequency. The same results were obtained for the O- and X-mode radio signals. A surprising finding was a constant phase difference between the pulsations in the ionosphere and on the ground for all frequencies below the local field line resonance frequency, independent of season or local time. These observations have been compared with theoretical predictions of the amplitude and phase of ionospheric Doppler oscillations driven by downgoing Alfvén mode waves. Our results agree with these predictions at or very near the field line resonance frequency but not at other frequencies. We conclude that the majority of the observations, which are for pulsations below the resonant frequency, are associated with downgoing fast mode waves, and models of the wave-ionosphere interaction need to be modified accordingly.Key words. Ionosphere (ionosphere irregularities) · Magnetospheric physics (magnetosphere-ionosphere interactions) · Radio science (ionospheric physics)

scholarly journals MHD theory of field line resonance in the magnetosphere

1992 ◽  
Author(s):  
C.Z. Cheng ◽  
T.C. Chang ◽  
C.A. Lin ◽  
W.H. Tsai
Keyword(s):  
Field Line ◽  
Field Line Resonance ◽  
Line Resonance
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