Bistatic HF radar diagnostics induced field‐aligned irregularities

Yampolski, Yu. M.; Beley, V. S.; Kascheev, S. B.; Koloskov, A. V.; Somov, V. G.; Hysell, D. L.; Isham, B.; Kelley, M. C.

doi:10.1029/97ja00037

Cited by 33 publications

(36 citation statements)

References 4 publications

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“…According to Eq. (4), oscillations of the ionospheric current are coupled with oscillations of the magnetic field-aligned currents (FACs), which are carried by shear Alfvén waves in the magnetosphere (Yampolski et al, 1997;Robinson et al, 2000;Papadopoulos et al, 1990;Cohen et al, 2010). A recent study by Papadopoulos et al (2011) demonstrates that shear Alfvén waves can also be generated by variations in the plasma pressure in the ionospheric F-region caused by the heating.…”

Section: Resultsmentioning

confidence: 99%

Excitation of zero-frequency magnetic field-aligned currents by ionospheric heating

Streltsov

Pedersen

2011

Ann. Geophys.

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Abstract. Time-dependent, three-dimensional numerical simulations of the reduced MHD model describing shear Alfvén waves in the magnetosphere provide an interesting prediction superficially similar to results of several ionospheric heating experiments conducted at high altitudes. In these experiments, heating of the ionospheric F-region with a constant/zero-frequency beam of HF waves causes luminous structures in the ionosphere in the form of a ring or a solid spot with a characteristic size comparable to the size of the heated spot. Simulations suggest that spots/rings or similar optical appearance might be associated with a magnetic fieldaligned current system produced by the ionospheric heating. Two of the most interesting features of this current system are (1) strong localization across the ambient magnetic field and (2) distinctive non-symmetrical luminous signatures (ring/spot) in magnetically conjugate locations in the ionosphere.

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Section: Resultsmentioning

confidence: 99%

Excitation of zero-frequency magnetic field-aligned currents by ionospheric heating

Streltsov

Pedersen

2011

Ann. Geophys.

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“…The Doppler shifts of the irregularities are closely related to the ambient E×B drift velocity and can be used to diagnose both the background electric field and also fields associated with MHD waves (e.g. Yampolski et al, 1997). Artificial F region FAIs are therefore important not only for studying heatingrelated phenomena but also for diagnosing aeronomic and magnetosphere-ionosphere coupling processes.…”

Section: Subsequent Observations Of Artificially Induced Fais Werementioning

confidence: 99%

30 MHz radar observations of artificial E region field-aligned plasma irregularities

Hysell

2008

Ann. Geophys.

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Abstract. Artificial E region field aligned irregularities (FAIs) have been observed during heating experiments at the HAARP facility using a new 30 MHz coherent scatter radar imager deployed near Homer, Alaska. Irregularities were observed during brief experiments on three quiet days in July and August, 2007, when the daytime E region critical frequency was close to 3 MHz. Irregularities were consistently generated and detected during experiments with O-mode HF pumping on zenith with a 1-min on, 1-min off CW modulation. The scattering cross sections, rise, and fall times of the echoes were observed as well as their spectral properties. Results were found to be mainly in agreement with observations from other mid-and high-latitude sites with some discrepancies. Radar images of the irregularity-filled volume on one case exhibited clear variations in backscatter power and Doppler shift across the volume. The images furthermore show the emergence of a small irregularity-filled region to the south southwest of the main region in the approximate direction of magnetic zenith.

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“…We report experimental results related to probing medium-scale traveling ionospheric disturbances using HF-induced scatter targets at mid-and high latitudes. With bi-static HF Doppler scatter, the AFAIs are being studied at middle (Blagoveshchenskaya and Troshichev, 1996;Yampolski et al, 1997;Blagoveshchenskaya et al, 1998a) and high latitudes (Blagoveshchenskaya et al, 1998b(Blagoveshchenskaya et al, , 1999(Blagoveshchenskaya et al, , 2006Rietveld et al, 2003). The proposed observational technique was used for the first time to identify the medium-scale TIDs.…”

Section: Introductionmentioning

confidence: 99%

Probing of medium-scale traveling ionospheric disturbances using HF-induced scatter targets

et al. 2006

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Abstract.Experimental results from the Tromsø and Sura heating experiments at high and mid-latitudes are examined. It is shown that the combination of HF-induced target and bi-static HF Doppler radio scatter observations is a profitable method for probing medium-scale traveling ionospheric disturbances (TIDs) at high and mid-latitudes. HF ionospheric modification experiments provide a way of producing the HF-induced scatter target in a controlled manner at altitudes where the sensitivity to TIDs is highest. Bi-static HF Doppler radio scatter observations were carried out on the LondonTromsø-St. Petersburg path in the course of a Tromsø heating experiment on 16 November 2004 when the pump wave was reflected from an auroral Es-layer. During Sura heating experiments on 19 and 20 August 2004, when the HF pump wave was reflected from the F2 ionospheric layer, multiposition bi-static HF Doppler radio scatter observations were simultaneously performed at three reception points including St. Petersburg, Kharkov, and Rostov-on-Don. Ray tracing and Doppler shift simulations were made for all experiments. A computational technique has been developed allowing the reconstruction of the TID phase velocities from multi-position bi-static HF Doppler scatters. Parameters of medium-scale TIDs were found. In all experiments they were observed in the evening and pre-midnight hours. TIDs in the auroral E-region with periods of about 23 min were traveling southward at speeds of 210 m/s. TIDs in the mid-latitudinalCorrespondence to: N. F. Blagoveshchenskaya (nataly@aari.nw.ru) F-region with periods from 20 to 45 min travelled at speeds between 40 and 150 m/s. During quiet magnetic conditions the waves were traveling in the north-east direction. In disturbed conditions the waves were moving in the south-west direction with higher speeds as compared with quiet conditions. Possible sources for the atmospheric gravity waves at middle and high latitudes are discussed.

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Bistatic HF radar diagnostics induced field‐aligned irregularities

Cited by 33 publications

References 4 publications

Excitation of zero-frequency magnetic field-aligned currents by ionospheric heating

Excitation of zero-frequency magnetic field-aligned currents by ionospheric heating

30 MHz radar observations of artificial E region field-aligned plasma irregularities

Probing of medium-scale traveling ionospheric disturbances using HF-induced scatter targets

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