Changes of the first Schumann resonance frequency during relativistic solar proton precipitation in the 6 November 1997 event

Roldugin, V. K.; Maltsev, Y. P.; Vasiljev, A. N.; Vashenyuk, É. V.

doi:10.1007/s005850050856

Cited by 8 publications

(23 citation statements)

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“…During solar activity there may be two kinds of changes: (1) increase in ionization level at the normal D-region reflection heights, and (2) the variation of D-region's lower edge (Roldugin et al 1999). According to this model the variation in the first SR frequency is given by (Roldugin et al 1999) .…”

Section: Resultsmentioning

confidence: 99%

“…This fact contributes additionally to the increase in the first SR frequency. During a SPE energetic protons can penetrate deeply into the ionosphere up to 50 km and can ionize regions lower than the normal D-region (Roldugin et al 1999;Clilverd et al 2006). In this case h 1 changes by the value 1 d .…”

Section: Resultsmentioning

confidence: 99%

“…The various aspects of SR phenomena are being explored (Balser and Wagner 1960;Madden and Thompson 1965;Ogawa et al 1969;Sao et al 1973;Tanahashi 1976;Sentman 1983;Williams 1992;Füllekrug 1995;Füllekrug and Fraser-Smith 1996;Yampolski et al 1997;Heckman et al 1998;Nickolaenko et al 1998Nickolaenko et al , 1999Balling and Hildebrandt 2000;Hobara et al 2000;Shvets 2001;Hayakawa 2002, 2007;Sekiguchi et al 2006) over the years. The seasonal and day-to-day variability in SR intensities, frequencies, and quality factors are reported with possible explanations for such changes (Balser and Wagner 1962;Galejs 1970;Cannon and Rycroft 1982;Nickolaenko and Rabinowicz 1995;Sátori 1996;Roldugin et al 1999Roldugin et al , 2001Roldugin et al , 2003Roldugin et al , 2004Price and Melnikov 2004;Melnikov et al 2004;Sekiguchi et al 2008). These changes are interpreted mainly by the influence of the temporal and spatial variations in the inhomogeneity and conductivity of the medium along with the variations in location and intensities of the three global thunderstorm generating centers.…”

Section: Introductionmentioning

confidence: 99%

“…It causes the whole polar ionosphere to shift downward causing the first SR mode frequency to move globally to lower values (Schlegel and Füllekrug 1999;Roldugin et al 1999Roldugin et al , 2001Roldugin et al , 2003. Protons with energy up to 100 MeV are most often emitted from the Sun in conjunction with solar flares, which can penetrate deeply into the D-region and cause additional ionization leading to the conductivity changes thereby modifying the SR parameters (Roldugin et al 1999(Roldugin et al , 2001(Roldugin et al , 2003. High solar proton fluxes cause serious radiation hazards in the solar system (Reedy 2006).…”

Section: Introductionmentioning

confidence: 99%

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First Mode Schumann Resonance Frequency Variation During a Solar Proton Event

Sanfui¹,

Biswas²

2016

Terr. Atmos. Ocean. Sci.

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A severe X-ray flare occurred on 06 -07 March 2012 followed by a solar proton event (SPE). During this event we studied the variation in frequency of the first Schumann resonance (SR) spectra mode from the recorded data over Kolkata (22.56°N, 88.5°E). The first mode frequency enhanced (~8.14 Hz, 3.85%) during the solar X-ray bursts and immediately after its value decreased (~7.44 Hz, 5.13%) during the proton event. The influences of SPE and X-ray bursts upon the SR frequency fluctuation are explained in terms of the changes in medium ionization, i.e., the change in dielectric property and two layer reflection height variation in the waveguide. The geomagnetic storm effect on the modification of this frequency variation occurring during that time is also considered.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

First Mode Schumann Resonance Frequency Variation During a Solar Proton Event

Sanfui¹,

Biswas²

2016

Terr. Atmos. Ocean. Sci.

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“…Any change in the electrons density in lower ionosphere modifies its dielectric permeability, which plays an important role in modifying the SR frequency. Roldugin et al (1999) showed that the SR frequency depends both on the electron density in the ionospheric Dregion and on the base height of this region. For the interpretation of our data, we now consider, in some detail, the simple model of Roldugin et al (2003), for which the authors establish a quantitative relation between SR frequencies and the ionospheric parameters.…”

Section: Estimation Of Electron Density In Lower Ionospherementioning

confidence: 99%

Schumann resonance frequency variations observed in magnetotelluric data recorded from Garhwal Himalayan region India

2009

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Abstract. Schumann resonance (SR) frequency variation has been studied using Magnetotelluric (MT) data recorded in one of the world's toughest and generally inaccessible Himalayan terrain for the first time in the author's knowledge. The magnetotelluric data, in the form of orthogonal time varying electric and magnetic field components (E x , E y , B x and B y ), recorded during 10 March-23 May 2006, in the Himalayan region, India, at elevations between 1228-2747 m above mean sea level (amsl), were used to study the SR frequency variation. Electromagnetic field components, in the form of time series, were recorded at 64 Hz sampling frequency at a site located away from the cultural noise. Spectral analysis of time series data, at a frequency resolution of 0.03 Hz, has been performed using Fast Fourier Transform (FFT) algorithm. Spectral stabilization in three Schumann resonance modes is achieved by averaging the power spectral magnitude of 32 data segments, each with 2048 sample data. Amplitude variation in the Schumann resonance frequency associated with day-night, sunrise and terminator effect was observed. Average diurnal variation in the first three Schumann resonance frequencies associated with magnetic field components is presented. The maximum frequency variation of about 0.3, 0.4 and 0.7 Hz was observed in the first, second and third mode, respectively. The frequency variations observed in electric and magnetic field components also show phase shift and varying attenuation. The SR frequency variation has been used to define the ionospheric electron density variation in the Himalayan region, India.Keywords. Ionosphere (Electric fields and currents) -Meteorology and atmospheric dynamics (Lightning) -Radio science (Electromagnetic noise and interference)Correspondence to: R. Chand

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Studies of the variations of the first Schumann resonance frequency during the solar flare on 7 March 2012

Zhou

Xiaolin

2015

JGR Atmospheres

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The ELF measurements at the YS station in China during the X5.4 solar flare on 7 March 2012 are examined. The first modal Schumann resonance (SR) frequencies of the horizontal magnetic field components were found to increase by 0.1-0.2 Hz during the X-ray burst. During the enhancement of the proton flux, the first modal frequency of the east-west magnetic field component decreases by approximately 0.6 Hz at most, while the variation in the north-south magnetic field component is less well defined. The mechanisms of the variations are simulated with a finite difference time domain technique by modeling the perturbed conductivity profile in the day-night asymmetric Earth-ionosphere cavity and modeling the global lightning source with the raw flash data measured by satellites. The simulated varying trends of the SR frequencies observed near the ground with the altitudes of the conductivity perturbations are nearly the same as those previously reported and are interpreted by the two characteristic height model first proposed by Greifinger and Greifinger. It is concluded that the SR frequencies increase for enhanced conductivity above the altitude of 60-70 km because of the lowered magnetic height and decrease for enhanced conductivity below this altitude due to the lowered electric height. This finding can explain the opposite behaviors of the SR frequencies during X-ray bursts and strong solar proton events (SPEs). The simulation model in this work proved to be effective, with the simulated shifts in the values of SR frequencies during X-ray bursts and SPEs being close to the practical measurements. IntroductionThe Schumann resonance (SR) is excited by the global thunderstorms and propagates with low attenuation in the closed waveguide confined by the Earth's surface and the lower ionosphere. The SR parameters, including the modal frequencies, amplitudes, and Q values, have robust relationships with the global lightning activity, and the inverse electromagnetic problem aimed at reducing the distribution of global lightning activity from the SR records has been proven to be feasible and has become a popular topic of study in the past few decades [Nickolaenko et al., 1998;Shvets et al., 2009Shvets et al., , 2010Ondrášková et al., 2011]. Due to the close correlations between the global lightning activity and the climate, the SR can also be used to detect the slight fluctuations in the tropical atmosphere temperature, the content of the upper tropospheric water vapor and the position of the lightning activity in El Niño and La Niña years; these studies have received great attention in the past few decades [Williams, 1992;Kent et al., 1995;Sátori and Zieger, 1999;Price, 2000;Sekiguchi et al., 2006;Sátori et al., 2009].Meanwhile, the characteristics of the SR also depend on the electrical properties of the lower ionosphere, which are strongly associated with the solar activity at different time scales. There are multiple studies demonstrating clear links of the SR parameters with the solar X-ray radiation variati...

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Changes of the first Schumann resonance frequency during relativistic solar proton precipitation in the 6 November 1997 event

Cited by 8 publications

References 8 publications

First Mode Schumann Resonance Frequency Variation During a Solar Proton Event

First Mode Schumann Resonance Frequency Variation During a Solar Proton Event

Schumann resonance frequency variations observed in magnetotelluric data recorded from Garhwal Himalayan region India

Studies of the variations of the first Schumann resonance frequency during the solar flare on 7 March 2012

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