Strong influence of solar X-ray flares on low-frequency electromagnetic signals in middle latitudes

Abstract. In this paper we analysed sudden phase anomalies (SPAs) of VLF–LF signals recorded at Graz (Austria), Birr (Ireland) and Moscow (Russia) stations during two strong solar flares in September 2017. The first X-class 9.3 flare occurred on 6 September at 12:02 UT, and the second X-class 8.2 flare was observed on 10 September 2017 at 16:06 UT. Data from seven transmitters in a frequency range between 20 and 45 kHz are used for the analysis. The SPAs were observed in all middle-latitude paths (differently orientated) with path lengths from 350 to 7000 km. Solar X-ray burst data were taken from GOES satellite observations in the wavelength band of 0.05–0.4 nm. It was found that (i) the amplitude of SPAs in different paths varies from 10 to 282∘, and (ii) the correlation between the amplitudes of SPAs, the lengths of paths and the signal frequency is weak. The change in effective height of reflection due to lowering of the reflecting layer during the flares was found to be about 12 km for the first event and about 9 km for the second event. Spectral analysis of the X-ray and LF data, filtered in the range between 5 s and 16 min, showed that the LF signal spectra are very similar to X-ray spectra. Maxima of both X-ray and LF spectra are in 2–16 min interval.

Download Full-text

Strong influence of solar X-ray flares on low-frequency electromagnetic signals in middle latitudes

10.5194/angeo-2019-53 ◽

2019 ◽

Author(s):

Alexandr Rozhnoi ◽

Mariya Solovieva ◽

Viktor Fedun ◽

Peter Gallagher ◽

Joseph McCauley ◽

...

Keyword(s):

Solar Flares ◽

Low Frequency ◽

Signal Frequency ◽

Frequency Range ◽

Effective Height ◽

X Ray ◽

Middle Latitudes ◽

Burst Data ◽

Path Lengths ◽

Electromagnetic Signals

Abstract. In this paper we analysed Sudden Phase Anomalies (SPAs) of VLF/LF signals recorded at Graz (Austria), Birr (Ireland) and Moscow (Russia) stations during two strong solar flares in September 2017. The first X-class 9.3 flare occurred on 6 September at 12:02 UT and the second X-class 8.2 flare was observed on 10 September 2017 at 16:06 UT. Data from seven transmitters in a frequency range between 20–45 kHz are used for the analysis. The SPAs were observed in all middle-latitudes paths (differently orientated) with path lengths from 350 km to 7000 km. Solar X-ray burst data were taken from GOES satellite observations in the wavelength band of 0.05–0.4 nm. If was found that (i) the amplitude of SPAs in different paths varies from 10 to 282 degrees, and (ii) the correlation between the amplitudes of SPAs, the lengths of paths and the signal frequency is weak. The change in effective height of reflection due to lowering of the reflecting layer during the flares was found to be about 12 km for the first event and about 9 km for the second event. Spectral analysis of the X-ray and LF data, filtered in the range between 5 s and 16 min, showed that the LF signal spectra are very similar to X-ray spectra. Maxima of both X-ray and LF spectra are in 2–16 min interval.

Download Full-text

Classification of X-ray solar flares regarding their effects on the lower ionosphere electron density profile

Annales Geophysicae ◽

10.5194/angeo-26-1731-2008 ◽

2008 ◽

Vol 26 (7) ◽

pp. 1731-1740 ◽

Cited By ~ 46

Author(s):

D. P. Grubor ◽

D. M. Šulić ◽

V. Žigman

Keyword(s):

Electron Density ◽

Solar Flares ◽

Low Frequency ◽

Lower Ionosphere ◽

Electron Density Profile ◽

Height Range ◽

X Ray ◽

Reflection Height ◽

Single Trace

Abstract. The classification of X-ray solar flares is performed regarding their effects on the Very Low Frequency (VLF) wave propagation along the Earth-ionosphere waveguide. The changes in propagation are detected from an observed VLF signal phase and amplitude perturbations, taking place during X-ray solar flares. All flare effects chosen for the analysis are recorded by the Absolute Phase and Amplitude Logger (AbsPal), during the summer months of 2004–2007, on the single trace, Skelton (54.72 N, 2.88 W) to Belgrade (44.85 N, 20.38 E) with a distance along the Great Circle Path (GCP) D≈2000 km in length. The observed VLF amplitude and phase perturbations are simulated by the computer program Long-Wavelength Propagation Capability (LWPC), using Wait's model of the lower ionosphere, as determined by two parameters: the sharpness (β in 1/km) and reflection height (H' in km). By varying the values of β and H' so as to match the observed amplitude and phase perturbations, the variation of the D-region electron density height profile Ne(z) was reconstructed, throughout flare duration. The procedure is illustrated as applied to a series of flares, from class C to M5 (5×10−5 W/m2 at 0.1–0.8 nm), each giving rise to a different time development of signal perturbation. The corresponding change in electron density from the unperturbed value at the unperturbed reflection height, i.e. Ne(74 km)=2.16×108 m−3 to the value induced by an M5 class flare, up to Ne(74 km)=4×1010 m−3 is obtained. The β parameter is found to range from 0.30–0.49 1/km and the reflection height H' to vary from 74–63 km. The changes in Ne(z) during the flares, within height range z=60 to 90 km are determined, as well.

Download Full-text

A comparative study of measured amplitude and phase perturbations of VLF and LF radio signals induced by solar flares

Serbian Astronomical Journal ◽

10.2298/saj1488045s ◽

2014 ◽

pp. 45-54 ◽

Cited By ~ 10

Author(s):

D.M. Sulic ◽

V.A. Sreckovic

Keyword(s):

Solar Flares ◽

Low Frequency ◽

Geographic Location ◽

Electron Density Profile ◽

Great Circle ◽

Direct Result ◽

Ionospheric Disturbances ◽

X Ray ◽

Radio Signals ◽

Middle Europe

Very Low Frequency (VLF) and Low Frequency (LF) signal perturbations were examined to study ionospheric disturbances induced by solar X-ray flares in order to understand processes involved in propagation of VLF/LF radio signals over short paths and to estimate specific characteristics of each short path. The receiver at the Belgrade station is constantly monitoring the amplitude and phase of a coherent and subionospherically propagating LF signal operated in Sicily NSC at 45.90 kHz, and a VLF signal operated in Isola di Tavolara ICV at 20.27 kHz, with the great circle distances of 953 km and 976 km, respectively. A significant number of similarities between these short paths is a direct result of both transmitters and the receiver?s geographic location. The main difference is in transmitter frequencies. From July 2008 to February 2014 there were about 200 events that were chosen for further examination. All selected examples showed that the amplitude and phase of VLF and LF signals were perturbed by solar X-ray flares occurrence. This six-year period covers both minimum and maximum of solar activity. Simultaneous measurement of amplitude and phase of the VLF/LF signals during a solar flare occurrence was applied to evaluate the electron density profile versus altitude, to carry out the function of time over the middle Europe.

Download Full-text

Problems in Thin-Film X-ray Quantification

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100135897 ◽

1990 ◽

Vol 48 (2) ◽

pp. 458-459

Author(s):

J N Chapman ◽

W A P Nicholson

Keyword(s):

Thin Film ◽

Specimen Thickness ◽

X Rays ◽

Characteristic Peak ◽

Local Composition ◽

X Ray ◽

Measured Ratio ◽

Path Lengths ◽

Composition Changes

Energy dispersive x-ray microanalysis (EDX) is widely used for the quantitative determination of local composition in thin film specimens. Extraction of quantitative data is usually accomplished by relating the ratio of the number of atoms of two species A and B in the volume excited by the electron beam (nA/nB) to the corresponding ratio of detected characteristic photons (NA/NB) through the use of a k-factor. This leads to an expression of the form nA/nB = kAB NA/NB where kAB is a measure of the relative efficiency with which x-rays are generated and detected from the two species.Errors in thin film x-ray quantification can arise from uncertainties in both NA/NB and kAB. In addition to the inevitable statistical errors, particularly severe problems arise in accurately determining the former if (i) mass loss occurs during spectrum acquisition so that the composition changes as irradiation proceeds, (ii) the characteristic peak from one of the minority components of interest is overlapped by the much larger peak from a majority component, (iii) the measured ratio varies significantly with specimen thickness as a result of electron channeling, or (iv) varying absorption corrections are required due to photons generated at different points having to traverse different path lengths through specimens of irregular and unknown topography on their way to the detector.

Download Full-text

The occurrence of single hard x-ray sources in solar flares

Advances in Space Research ◽

10.1016/s0273-1177(03)90419-4 ◽

2003 ◽

Vol 32 (12) ◽

pp. 2483-2488

Author(s):

C GOFF ◽

S MATTHEWS ◽

L HARRA

Keyword(s):

Solar Flares ◽

X Ray

Download Full-text

PEMANFAATAN RADIASI ENERGI TEGANGAN 150 KV UNTUK LAMPU LED PENERANGAN JALAN

Jurnal Teknik ◽

10.31000/jt.v7i1.936 ◽

2018 ◽

Vol 7 (1) ◽

Author(s):

Mauludi Manfaluthy

Keyword(s):

Magnetic Field ◽

Electric Field ◽

High Voltage ◽

Low Frequency ◽

Energy Utilization ◽

World Health ◽

Electromagnetic Signals ◽

Health Organization ◽

The Magnetic Field ◽

Low Frequency Waves

WHO (World Health Organization) concludes that not much effect is caused by electric field up to 20 kV / m in humans. WHO standard also mentions that humans will not be affected by the magnetic field under 100 micro tesla and that the electric field will affect the human body with a maximum standard of 5,000 volts per meter. In this study did not discuss about the effect of high voltage radiation SUTT (High Voltage Air Channel) with human health. The research will focus on energy utilization of SUTT radiation. The combination of electric field and magnetic field on SUTT (70-150KV) can generate electromagnetic (EM) and radiation waves, which are expected to be converted to turn on street lights around the location of high voltage areas or into other forms. The design of this prototype works like an antenna in general that captures electromagnetic signals and converts them into AC waves. With a capacitor that can store the potential energy of AC and Schottky diode waves created specifically for low frequency waves, make the current into one direction (DC). From the research results obtained the current generated from the radiation is very small even though the voltage is big enough.Keywords : Radiance Energy, Joule Thief, and LED Module.

Download Full-text

Low-frequency ultrasound and photochromotherapy in the complex treatment of patients with chronic bacterial and viral rhinosinusitis

Terapevt (General Physician) ◽

10.33920/med-12-2003-02 ◽

2020 ◽

pp. 13-23

Author(s):

Natalya Kornova ◽

A. Krylov

Keyword(s):

Chronic Rhinosinusitis ◽

Low Frequency ◽

Chronic Tonsillitis ◽

Complex Treatment ◽

Resonance Imaging ◽

X Ray ◽

Low Frequency Ultrasound ◽

Viral Nature ◽

Ig G ◽

Frequency Ultrasound

The article presents results of a study on the effectiveness of using lowfrequency ultrasound and photochromotherapy in the complex treatment of patients with chronic bacterial and viral rhinosinusitis. The study involved 69 people aged 18 to 55 years: 39 (56.83 %) women and 30 (45.11 %) men with chronic rhinosinusitis during the period of clinical exacerbation and concomitant chronic tonsillitis without exacerbation. All patients included in the study underwent X-ray examination or computed tomography and magnetic resonance imaging of the paranasal sinuses. 100 % of the patients were examined for the presence of antibodies to Human gammaherpesvirus 4 (ELISA), had study of blood serum for IgM and IgG and test to determine the avidity of Ig G antibodies to γ-herpesviruses. The obtained data indicate the effectiveness of including low-frequency ultrasound and photochromotherapy in the complex treatment of patients with chronic rhinosinusitis and concomitant chronic tonsillitis of bacterial and viral nature without exacerbation.

Download Full-text

Theoretically derived thermodynamic properties can be improved by the refinement of low-frequency modes against X-ray diffraction data

Chemical Communications ◽

10.1039/d1cc02608a ◽

2021 ◽

Author(s):

Anna Agnieszka Hoser ◽

Marcin Sztylko ◽

Damian Trzybiński ◽

Anders Østergaard Madsen

Keyword(s):

Thermodynamic Properties ◽

Dft Calculations ◽

Diffraction Data ◽

Molecular Crystals ◽

Low Frequency ◽

X Ray Diffraction ◽

X Ray ◽

Efficient Approach

A framework for estimation of thermodynamic properties for molecular crystals via refinement of frequencies from DFT calculations against X-ray diffraction data is presented. The framework provides an efficient approach to...

Download Full-text