Studies on the shift in the frequency of the first Schumann resonance mode during a solar proton event

De, S. S.; De, B. K.; Bandyopadhyay, Bidhan C.; Paul, Suman; Haldar, D.P.; Barui, S.

doi:10.1016/j.jastp.2010.04.004

Cited by 23 publications

(14 citation statements)

References 39 publications

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“…Quantitative estimations on the ionosphere modifications relevant to the particular SPEs were provided in their later work [ Rabinowicz et al , ]. De et al [] compared the variation of the first SR frequency observed at Kolkata station in India during the SPE on 14 July 2000 with those measured at other stations at higher latitudes, and they obtained the same results: the SR frequency increased with the X‐ray radiation and decreased with the solar proton flux.…”

Section: Introductionmentioning

confidence: 93%

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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Section: Introductionmentioning

confidence: 93%

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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“…SR is a global electromagnetic resonance, and its parameters reflect the variations of both lightning activities and the electrical parameters in the Earth‐ionosphere cavity. So any SR anomaly is either attributed to the abnormal variations of the lightning source, such as the variations of SR power related to El Niño and La Niña phenomena [ Sátori and Zieger , ; Yang and Pasko , ], or the abnormal modifications of the electrical parameters in the Earth‐ionosphere cavity, such as the variations of SR parameters during solar proton events [ Schlegel and Füllekrug , ; Roldugin et al ., ; Roldugin et al ., ; De et al ., ] and gamma ray burst events[ Price and Mushtak , ; Nickolaenko et al ., ]. Seismic activity is induced by the outbreak of the pressure inside the Earth and affects SR during its preparation process by two possible fashions: Surface electromagnetic radiations by crustal microfracturing contain the energy in SR band, which directly cause the SR anomaly. Due to some lithosphere‐atmosphere‐ionosphere coupling (LAIC) mechanisms, the electrical parameters of the Earth‐ionosphere cavity changed and triggered the propagation anomaly of SR.…”

Section: Introductionmentioning

confidence: 99%

Anomalous phenomena in Schumann resonance band observed in China before the 2011 magnitude 9.0 Tohoku‐Oki earthquake in Japan

Zhou

Xiaolin

et al. 2013

JGR Atmospheres

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[1] The anomalous phenomena in the Schumann resonance (SR) band, possibly associated with the Tohoku-Oki earthquake (EQ), are studied based on the ELF observations at two stations in China. The anomaly appeared on 8 March, 3 days prior to the main shock, and was characterized by an increase in the intensity at frequencies from the first mode to the fourth mode in both magnetic field components, different from the observations in Japan before large EQs in Taiwan. The abnormal behaviors of the north-south and east-west magnetic field components primarily appeared at 0000-0900 UT and 0200-0900 UT on 8 March, respectively. The finite difference time domain numerical method is applied to model the impact of seismic process on the ELF radio propagation. A partially uniform knee model of the vertical conductivity profile suggested by V. C. Mushtak is used to model the day-night asymmetric Earth-ionosphere cavity, and a locally EQ-induced disturbance model of the atmospheric conductivity is introduced. The atmospheric conductivity is assumed to increase around the epicenter according to the localized enhancement of total electron content in the ionosphere. It is concluded that the SR anomalous phenomena before the Tohoku-Oki EQ have much to do with the excited sources located at South America and Asia and also with the localized distribution of the disturbed conductivity. This work is a further confirmation of the relationship of SR anomalies with large EQs and has further concluded that the distortions in the SR band before large EQs may be caused by the irregularities located over the shock epicenter in the Earth-ionosphere cavity by numerical method.

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“…The last topic has received considerable interest over the past few years. Effects primarily on SR frequencies have been detected during cosmic gamma-ray bursts [177,178], solar flares and solar proton events [62,[178][179][180], as well as over the 11-year solar cycle [181][182][183]. Despite these remaining open problems, SR is one of the most promising tools in a variety of fields related to lightning electromagnetics.…”

Section: Discussionmentioning

confidence: 99%

“…A 10 minute interval was used in the first successful experiment [7,8]. While SR observations have been ongoing for many years in Hungary [59], USA [26], Japan [60], and Israel [54], recently new observatories have been opened in Poland [61], India [62], China [63,64], Greece [65] and Spain [66].…”

Section: Sr Background Observations Of Global Lightning Activitymentioning

confidence: 99%

ELF Electromagnetic Waves from Lightning: The Schumann Resonances

Price

2016

Atmosphere

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Lightning produces electromagnetic fields and waves in all frequency ranges. In the extremely low frequency (ELF) range below 100 Hz, the global Schumann Resonances (SR) are excited at frequencies of 8 Hz, 14 Hz, 20 Hz, etc. This review is aimed at the reader generally unfamiliar with the Schumann Resonances. First some historical context to SR research is given, followed by some theoretical background and examples of the extensive use of Schumann resonances in a variety of lightning-related studies in recent years, ranging from estimates of the spatial and temporal variations in global lighting activity, connections to global climate change, transient luminous events and extraterrestrial lightning. Both theoretical and experimental results of the global resonance phenomenon are presented. It is our hope that this review will increase the interest in SR among researchers previously unfamiliar with this phenomenon.

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Studies on the shift in the frequency of the first Schumann resonance mode during a solar proton event

Cited by 23 publications

References 39 publications

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

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

Anomalous phenomena in Schumann resonance band observed in China before the 2011 magnitude 9.0 Tohoku‐Oki earthquake in Japan

ELF Electromagnetic Waves from Lightning: The Schumann Resonances

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