scholarly journals An automatic method to determine the frequency scale of the ionospheric Alfvén resonator using data from Hylaty station, Poland

2006 ◽  
Vol 24 (8) ◽  
pp. 2151-2158 ◽  
Author(s):  
A. Odzimek ◽  
A. Kułak ◽  
A. Michalec ◽  
J. Kubisz
Keyword(s):  
Field Data ◽  
Automatic Method ◽  
Frequency Range ◽  
Magnetic Field Data ◽  
Ionospheric Alfvén Resonator ◽  
Frequency Scale ◽  
Alfven Resonator ◽  
Using Data ◽  
Ionospheric Alfven Resonator ◽  
Elf Magnetic Field

Abstract. ULF/ELF magnetic field data recorded at the "Hylaty" station in Poland (49°19' N, 22°56' E; L≃2) are analysed to find the characteristics of spectral resonance structures (SRS) in the frequency range 1–5 Hz, related to the ionospheric Alfvén resonator (IAR). An automatic procedure is employed to SRS events observed at "Hylaty" during the nighttime in 2001–2003, to calculate the parameter which determines the separation between the harmonics of the resonator, termed the frequency scale. Diurnal and seasonal variations of the frequency scale within the range of 0.4–0.8 Hz have been found. The usefulness and disadvantages of this particular method of SRS analysis, and of other methods, are discussed.

The splitting effect of the mode structure of the ionospheric alfven resonator

2015 ◽  
Vol 21 (1(92)) ◽  
pp. 58-63
Author(s):  
N.A. Baru ◽  
◽  
A.V. Koloskov ◽  
Y.M. Yampolski ◽  
◽  
...  
Keyword(s):  
Mode Structure ◽  
Ionospheric Alfvén Resonator ◽  
Alfven Resonator ◽  
Ionospheric Alfven Resonator ◽  
Splitting Effect

Pc 1 waves and ionospheric Alfvén resonator: Generation or filtration?

2000 ◽  
Vol 27 (23) ◽  
pp. 3805-3808 ◽  
Author(s):  
A. G. Demekhov ◽  
V. Yu. Trakhtengerts ◽  
T. Bösinger
Keyword(s):  
Ionospheric Alfvén Resonator ◽  
Alfven Resonator ◽  
Ionospheric Alfven Resonator

Coordination Of The Geosynchronous And Auroral Substorms

1996 ◽  
Author(s):  
Charles F. Kennel
Keyword(s):  
Magnetic Field ◽  
Field Data ◽  
Conjugate Point ◽  
Magnetic Field Data ◽  
Correlation Studies ◽  
Close Relationship ◽  
Initial Onset ◽  
Fine Structures ◽  
Spatio Temporal ◽  
Using Data

Studies using data from the ATS-5 geosynchronous spacecraft revealed a clear relationship between midnight region injection events near the spacecraft and auroral displays near the ATS magnetic conjugate point (Hones et al., 1971a; Mende et al., 1972; Eather et al., 1976; Mende and Shelley, 1976). A comparison of ATS-5 particle and magnetic field data with all-sky photographs taken at the conjugate point, Great Whale River, indicated that an injection at geostationary orbit generally corresponded to the brightening of the onset arc when the spacecraft was in the midnight sector (Akasofu et al., 1974). Results such as this whetted the collective appetite. How closely can the initial onset and injection be related to one another in time, do the onset and injection start on the same field field line, does the westward propagation of dipolarization correspond to the westward surge, can one relate the fine structures of the auroral expansion and the dipolarization? As time passed, increasingly precise answers have been given to these and similar questions, and auroral and geosynchronous substorm phenomenology has become more tightly integrated. In this chapter, we sample some of the evidence that supports this statement. The GEOS 2 spacecraft was stationed with its magnetic conjugate point near Kiruna, Sweden, so that the conjugate aurora could be studied with the extensive network of ground-based observatories in Scandinavia (Knott, 1975; Knott et al., 1979). In the first part of this chapter, we review some of the correlation studies carried out in the GEOS 2 project. In one particular series of four substorms, it was found that the dipolarization occurred at the same time as the aurora brightened and expanded poleward over the ground conjugate region (Section 14.2). In another case, a dispersionless injection at GEOS 2 corresponded to an intensification of the auroral X-ray band in Scandinavia (Section 14.2). Westward surges at the auroral conjugate point were associated with dipolarization at the spacecraft on a statistical basis (Section 14.3). Finally, the close relationship between both the auroral and geostationary substorm phenomena was extended to small spatio-temporal scales.

scholarly journals Ionospheric Alfvén resonator revisited: Feedback instability

2001 ◽  
Vol 106 (A11) ◽  
pp. 25813-25824 ◽  
Author(s):  
Oleg A. Pokhotelov ◽  
V. Khruschev ◽  
M. Parrot ◽  
S. Senchenkov ◽  
V. P. Pavlenko
Keyword(s):  
Ionospheric Alfvén Resonator ◽  
Alfven Resonator ◽  
Ionospheric Alfven Resonator

scholarly journals An effect of the ionospheric Alfvén resonator on multiband Pc1 pulsations

2004 ◽  
Vol 22 (2) ◽  
pp. 643-651 ◽  
Author(s):  
K. Prikner ◽  
K. Mursula ◽  
J. Kangas ◽  
R. Kerttula ◽  
F. Z. Feygin
Keyword(s):  
Ionospheric Alfvén Resonator ◽  
High Latitude Ionosphere ◽  
Distinct Frequency ◽  
Radar Measurements ◽  
Pc1 Pulsations ◽  
Alfven Resonator ◽  
Eiscat Radar ◽  
Ionospheric Alfven Resonator ◽  
Ionospheric Resonator ◽  
Large Frequency

Abstract. On 2 December 1999, the magnetometer stations in northern Finland registered structured Pc1 activity simultaneously in three distinct frequency bands. Using simultaneous EISCAT radar measurements of the high-latitude ionosphere, we have studied the ionospheric resonator properties during this multiband Pc1 event. The frequencies of the three structured Pc1 bands were found to closely correspond to the second, third and fourth harmonic of the calculated fundamental frequency of the ionospheric Alfvén resonator (IAR). In addition, those frequencies of the three pearl bands that were closest to the exact IAR harmonics were found to have the strongest intensities. The results demonstrate that the resonator can have an important role on ground-based Pc1 activity over a notably large frequency range, favoring transmission of waves with frequencies close to the resonator's eigenfrequencies. Since the frequencies of all three bands correspond to the maximum rather than the minimum of the transmission coefficient, the traditional bouncing wave packet model needs to be revised. Key words. Ionosphere (auroral ionosphere; ionosphere magnetosphere interactions; wave propagation)

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