scholarly journals Dynamic processes in the magnetic field and in the ionosphere during the 30 August–2 September 2019 geospace storm: influence on high frequency radio wave characteristics

2021 ◽  
Vol 39 (4) ◽  
pp. 657-685
Author(s):  
Yiyang Luo ◽  
Leonid Chernogor ◽  
Kostiantyn Garmash ◽  
Qiang Guo ◽  
Victor Rozumenko ◽  
...  
Keyword(s):  
Radio Wave ◽  
Electron Density ◽  
High Frequency ◽  
Geomagnetic Field ◽  
Recovery Phase ◽  
Radio Waves ◽  
Ionospheric Storm ◽  
Period Range ◽  
Multiple Method ◽  
S Period

Abstract. The concept that geospace storms are comprised of synergistically coupled magnetic storms, ionospheric storms, atmospheric storms, and storms in the electric field originating in the magnetosphere, the ionosphere, and the atmosphere (i.e., electrical storms) was validated a few decades ago. Geospace storm studies require the employment of multiple-method approaches to the Sun–interplanetary medium–magnetosphere–ionosphere–atmosphere–Earth system. This study provides general analysis of the 30 August–2 September 2019 geospace storm, the analysis of disturbances in the geomagnetic field and in the ionosphere, as well as the influence of the ionospheric storm on the characteristics of high frequency (HF) radio waves over the People's Republic of China. The main results of the study are as follows. The energy and power of the geospace storm have been estimated to be 1.5×1015 J and 1.5×1010 W, and thus, this storm is weak. The energy and power of the magnetic storm have been estimated to be 1.5×1015 J and 9×109 W, i.e., this storm is moderate, and a characteristic feature of this storm is the duration of the main phase of up to 2 d. The recovery phase also was lengthy and was no less than 2 d. On 31 August and 1 September 2019, the variations in the H and D components attained 60–70 nT, while the Z-component variations did not exceed 20 nT. On 31 August and 1 September 2019, the level of fluctuations in the geomagnetic field in the 100–1000 s period range increased from 0.2–0.3 to 2–4 nT, while the energy of the oscillations showed a maximum in the 300–400 to 700–900 s period range. During the geospace storm, a moderately to strongly negative ionospheric storm manifested itself by the reduction in the ionospheric F-region electron density by a factor of 1.4 to 2.4 times on 31 August and 1 September 2019, compared to the its values on the reference day. Appreciable disturbances were also observed to occur in the ionospheric E region and possibly in the Es layer. In the course of the ionospheric storm, the altitude of reflection of radio waves could sharply increase from ∼150 to ∼300–310 km. The atmospheric gravity waves generated within the geospace storm modulated the ionospheric electron density; for the ∼30 min period oscillation, the amplitude of the electron density disturbances could attain ∼40 %, while it did not exceed 6 % for the ∼15 min period. At the same time, the height of reflection of the radio waves varied quasi-periodically with a 20–30 km amplitude. The results obtained have made a contribution to the understanding of the geospace storm physics, to developing theoretical and empirical models of geospace storms, to the acquisition of detailed understanding of the adverse effects that geospace storms have on radio wave propagation, and to applying that knowledge to effective forecasting of these adverse influences.

scholarly journals Dynamic processes in the magnetic field and in the ionosphere during the 30 August–2 September, 2019 geospace storm

2020 ◽  
Author(s):  
Yiyang Luo ◽  
Leonid Chernogor ◽  
Kostiantyn Garmash ◽  
Qiang Guo ◽  
Victor Rozumenko ◽  
...  
Keyword(s):  
Electron Density ◽  
Geomagnetic Field ◽  
Unique Feature ◽  
Recovery Phase ◽  
Radiowave Propagation ◽  
Radio Waves ◽  
Ionospheric Storm ◽  
Period Range ◽  
Multiple Method ◽  
S Period

Abstract. Back at the end of the last century, L. F. Chernogor validated the concept that geospace storms are comprised of synergistically coupled magnetic storms, ionospheric storms, atmospheric storms, and storms in the electric field originating in the magnetosphere, the ionosphere and the atmosphere (i.e., electric storms). Their joint studies require the employment of multiple-method approach to the Sun–interplanetary medium–magnetosphere–ionosphere–atmosphere – Earth system. This study provides general analysis of the 30 August–2 September, 2019 geospace storm, the analysis of disturbances in the geomagnetic field and in the ionosphere, as well as the influence of the ionospheric storm on the characteristics of HF radio waves over the People's Republic of China. A unique feature of the geospace storm under study is its duration, of up to four days. The main results of the study are as follows. The energy and power of the geospace storm have been estimated to be 1.5 PJ and 15 GW, and thus this storm is weak. The energy and power of the magnetic storm have been estimated to be 1.5 PJ and 9 GW, i.e., this storm is moderate, and a unique feature of this storm is the duration of the main phase, of up to two days. The recovery phase also was lengthy, no less than two days. On 31 August 2019 and on 1 September 2019, the variations in the H and D components attained 60–70 nT, while the Z-component variations did not exceed 20 nT. On 31 August 2019 and on 1 September 2019, the level of fluctuations in the geomagnetic field in the 100–1000 s period range increased from from 0.2–0.3 nT to 2–4 nT, while the energy of the oscillations showed a maximum in the 300–400 s to 700–900 s period range. The geospace storm was accompanied by a moderate to strong negative ionospheric storm. During 31 August 2019 and 1 September 2019, the electron density in the ionospheric F region reduced by a factor of 1.4 to 2.4 times as compared to the values on the reference day. The geospace storm gave rise to appreciable disturbances also in the ionospheric E region, as well as in the Es layer. In the course of the ionospheric storm, the altitude of reflection of radiowaves could sharply increase from about 150 km to approximately 300–310 km. The geospace storm was accompanied by the generation of atmospheric gravity waves modulating the ionospheric electron density. For the about 30 min period oscillation, the amplitude of the electron density disturbances could attain about 40 %, while it did not exceed 6 % for the about 15 min period. The results obtained have made a contribution to understanding of the geospace storm physics, to developing theoretical and empirical models of geospace storms, to the acquisition of detailed understanding of the adverse effects that geospace storms have on radiowave propagation and to applying that knowledge to effective forecasting these adverse influences.

scholarly journals GEOMAGNETIC EFFECT OF TURKISH EARTHQUAKE OF JANUARY 24, 2020

2020 ◽  
Vol 25 (4) ◽  
pp. 276-289
Author(s):  
Y. Luo ◽  
◽  
L. F. Chernogor ◽  
K. P. Garmash ◽  
◽  
...  
Keyword(s):  
Fourier Transform ◽  
Flash Memory ◽  
Geomagnetic Field ◽  
Temporal Variations ◽  
Fixed Number ◽  
Mhd Waves ◽  
Geomagnetic Disturbances ◽  
Period Range ◽  
Geomagnetic Effect ◽  
S Period

Purpose:The main cause of geomagnetic disturbances are cosmic sources, processes acting in the solar wind and in the interplanetary medium, as well as large celestial bodies entering the terrestrial atmosphere. Earthquakes (EQs) also act to produce geomagnetic effects. In accordance with the systems paradigm, the Earth–atmosphere–ionosphere–magnetosphere system (EAIMS) constitute a unified system, where positive and negative couplings among the subsystems, as well as feedbacks and precondition among the system components take place. The mechanisms for the action of EQs and processes acting in the lithosphere on the geomagnetic field are poorly understood. It is considered that the EQ action is caused by cracking of rocks, fluctuating motion in the pore fluid, static electricity discharges, etc. In the course of EQs, the seismic, acoustic, atmospheric gravity waves (AGWs), and magnetohydrodynamic (MHD) waves are generated. The purpose of this paper is to describe the magnetic effects of the EQ, which took place in Turkey on 24 January 2020. Design/methodology/approach: The measurements are taken with the fluxmeter magnetometer delivering 0.5-500 pT sensitivity in the 1-1000 s period range, respectively, and in a wide enough studied frequency band within 0.001 to 1 Hz. The EM-II magnetometer with the embedded microcontroller digitizes the magnetometer signals and performs preliminary filtering over 0.5 s time intervals, while the external flash memory is used to store the filtered out magnetometer signals and the times of their acquisition. To investigate quasi-periodic processes in detail, the temporal variations in the level of the H and D components of the geomagnetic field were applied to the systems spectral analysis, which makes use of the short-time Fourier transform, the wavelet transform using the Morlet wavelet as a basis function, and the Fourier transform in a sliding window with a width adjusted to be equal to a fixed number of harmonic periods. Findings: The train of oscillations in the level of the D component observed 25.5 h before the EQ on 23 January 2020 is supposed to be associated with the magnetic precursor. The bidirectional pulse in the H component observed on 24 January 2020 could be due to the piston action of the EQ, which had generated an MHD pulse. The quasi-periodic variations in the level of the H and D components of the geomagnetic field, which followed 75 min after the EQ, were caused by a magnetic disturbance produced by the traveling ionospheric disturbances due to the AGWs launched by the EQ. The magnetic effect amplitude was estimated to be close to 0.3 nT, and the quasi-period to be 700-900 s. The amplitude of the disturbances in the electron density in the AGW field was estimated to be about 8 % and the period of 700-900 s. Damping oscillations in both components of the magnetic field were detected to occur with a period of approximately 120 s. This effect is supposed to be due to the shock wave generated in the atmosphere in the course of the EQ. Conclusions: The magnetic variations associated with the EQ and occurring before and during the EQ have been studied in the 1-1000 s period range. Key words: earthquake, fluxmeter magnetometer, quasi-periodic disturbance, seismic wave, acoustic-gravity wave, MHD pulse

scholarly journals Modelling the influence of meteoric smoke particles on artificial heating in the D-region

2021 ◽  
Vol 39 (6) ◽  
pp. 1055-1068
Author(s):  
Margaretha Myrvang ◽  
Carsten Baumann ◽  
Ingrid Mann
Keyword(s):  
Electron Temperature ◽  
Radio Wave ◽  
Electron Density ◽  
Electron Attachment ◽  
Radio Waves ◽  
Night Time ◽  
Smoke Particles ◽  
D Region ◽  
Meteoric Smoke ◽  
Artificial Heating

Abstract. We investigate if the presence of meteoric smoke particles (MSPs) influences the electron temperature during artificial heating in the D-region. By transferring the energy of powerful high-frequency radio waves into thermal energy of electrons, artificial heating increases the electron temperature. Artificial heating depends on the height variation of electron density. The presence of MSPs can influence the electron density through charging of MSPs by electrons, which can reduce the number of free electrons and even result in height regions with strongly reduced electron density, so-called electron bite-outs. We simulate the influence of the artificial heating by calculating the intensity of the upward-propagating radio wave. The electron temperature at each height is derived from the balance of radio wave absorption and cooling through elastic and inelastic collisions with neutral species. The influence of MSPs is investigated by including results from a one-dimensional height-dependent ionospheric model that includes electrons, positively and negatively charged ions, neutral MSPs, singly positively and singly negatively charged MSPs, and photochemistry such as photoionization and photodetachment. We apply typical ionospheric conditions and find that MSPs can influence both the magnitude and the height profile of the heated electron temperature above 80 km; however, this depends on ionospheric conditions. During night, the presence of MSPs leads to more efficient heating and thus a higher electron temperature above altitudes of 80 km. We found differences of up to 1000 K in electron temperature for calculations with and without MSPs. When MSPs are present, the heated electron temperature decreases more slowly. The presence of MSPs does not much affect the heating below 80 km for night conditions. For day conditions, the difference between the heated electron temperature with MSPs and without MSPs is less than 25 K. We also investigate model runs using MSP number density profiles for autumn, summer and winter. The night-time electron temperature is expected to be 280 K hotter in autumn than during winter conditions, while the sunlit D-region is 8 K cooler for autumn MSP conditions than for the summer case, depending on altitude. Finally, an investigation of the electron attachment efficiency to MSPs shows a significant impact on the amount of chargeable dust and consequently on the electron temperature.

Propagation Model of Multi-hop High-frequency Radio in Ocean Signal Attenuation

2020 ◽  
Vol 34 (14) ◽  
pp. 2058019
Author(s):  
Wenbin Liu ◽  
Dongbing Liu
Keyword(s):  
Radio Wave ◽  
High Frequency ◽  
Ocean Model ◽  
Propagation Model ◽  
Radio Waves ◽  
Analysis Method ◽  
Signal Attenuation ◽  
Modeling And Analysis ◽  
Reflection Model ◽  
The Difference

On the basis of propagation the characteristics of Multi-hop High-Frequency Radio waves in Marine environment, the modeling and analysis method of ocean signal reflection model are firstly introduced from the attenuation of the radio wave. Then the difference between the influence of ocean and earth on wireless communication is studied. By studying the influence of ship on the loss of radio wave propagation, the original ocean model is improved. Finally, an ocean signal reflection model suitable for different marine environments is obtained.

A QUANTITATIVE STUDY OF THE LIMITING POLARIZATION OF HIGH-FREQUENCY RADIO WAVES

1963 ◽  
Vol 41 (10) ◽  
pp. 1614-1622
Author(s):  
C. Abhirama Reddy
Keyword(s):  
Numerical Investigation ◽  
Electron Density ◽  
Quantitative Study ◽  
High Frequency ◽  
Hartree Equation ◽  
Radio Waves

A detailed numerical investigation of the characteristics of the "limiting region" in the ionosphere is carried out, using both Booker's criterion (1936) and Budden's equation (1952) for determining the "limiting region". The results show that, in the case of vertically downcoming high-frequency radio waves, the "limiting region" always occurs at levels of very low electron density for all conditions of normal layer propagation, thus justifying the method of computing the limiting polarization (from the Appleton–Hartree equation) with N = 0.The possibility that irregular ionization patches in the lowermost ionosphere might give rise to multiple "limiting levels" and thus affect the limiting polarization of downcoming radio waves is investigated; it is shown that such an effect, though theoretically possible, is not likely to occur frequently.

scholarly journals Modelling of the influence of meteoric smoke particles on artificial heating in the D-region

2021 ◽  
Author(s):  
Margaretha Myrvang ◽  
Carsten Baumann ◽  
Ingrid Mann
Keyword(s):  
Electron Temperature ◽  
Radio Wave ◽  
Electron Density ◽  
Radio Waves ◽  
Smoke Particles ◽  
Radio Wave Absorption ◽  
D Region ◽  
Meteoric Smoke ◽  
Artificial Heating ◽  
The Difference

Abstract. We investigate if the presence of meteoric smoke particles (MSP) influences the electron temperature during artfical heating in the D-region. The presence of MSP can result in height regions with reduced electron density, so-called electron bite-outs, due to charging of MSP by electrons. Artificial heating depends on the height variation of electron density. By transferring the energy of powerful high frequency radio waves into thermal energy of electrons, artificial heating increases the electron temperature. We simulate the influence of the artificial heating by calculating the intensity of the upward propagating radio wave. The electron temperature at each height is derived from the balance of radio wave absorption and cooling through elastic and inelastic collisions with neutral species. The influence of MSP is investigated by including results from a one-dimensional height-dependent ionospheric model that includes electrons, positively and negatively charged ions, neutral MSP, singly positively and singly negatively charged MSP and photo chemistry such as photo ionization and photo detachment. We apply typical ionospheric conditions and find that MSP can influence both the magnitude and the height profile of the heated electron temperature above 80 km, however this depends on ionospheric conditions. During night, the presence of MSP leads to more efficient heating, and thus a higher electron temperature, above altitudes of 80 km. We found differences up to 1000 K in temperature for calculations with and without MSP. When MSP are present, the heated electron temperature decreases more slowly. The presence of MSP does not much affect the heating below 80 km for night conditions. For day conditions, the difference between the heated electron temperature with MSP and without MSP is less than 25 K.

scholarly journals Geomagnetic effect of the Albanian earthquake on November 26, 2019

2020 ◽  
Keyword(s):  
Fourier Transform ◽  
Wavelet Transform ◽  
Geomagnetic Field ◽  
Earth Atmosphere ◽  
Period Range ◽  
Magnetohydrodynamic Waves ◽  
Geomagnetic Effect ◽  
The Earth ◽  
S Period ◽  
Atmospheric Gravity

Background. The main cause of geomagnetic disturbances is known to be space sources, processes acting in the solar wind and in the interplanetary medium, as well as falling large celestial bodies. Earthquakes also give rise to geomagnetic effects. In accordance with the systems paradigm, the Earth–atmosphere–ionosphere–magnetosphere system comprises the single system where direct and reverse, positive and negative coupling take place. The mechanism of the earthquake effect on the magnetic field is poorly understood. A rock cracking, a fluctuating movement of fluids in pores, a corona discharge of the high-voltage static charge, etc., are thought to be the processes that give rise to the geomagnetic effect. In the course of earthquakes, seismic, acoustic, atmospheric gravity, and magnetohydrodynamic waves are generated, which provide for coupling between the subsystems in the Earth–atmosphere–ionosphere–magnetosphere system. Purpose of Work. The paper describes the possible response in the level of the geomagnetic field to the earthquake of 26 November 2019 that took place in Albania. Techniques and Methodology. The measurements were taken with the fluxmeter magnetometer at the V. N. Karazin Kharkiv National University Magnetometer Observatory. It delivers 0.5 – 500 pT sensistivity in the 1–1000 s period range over a quite large frequency band of 0.001 to 1 Hz. To study the quasi-periodic processes in detail, the systems spectral analysis of the temporal dependences of the horizontal (H, D) geomagnetic field components has been employed. It includes the short-time Fourier transform, the Fourier transform in a sliding window with a width adjusted to be equal to a fixed number of harmonic periods, and wavelet transform, simultaneously. The wavelet transform employs the Morlet wavelet as a basis function. Results. The quasi-periodic variations in the level of the geomagnetic field observed to appear with a 6 min lag and to last for 70–80 min could be due to the earthquake. These disturbances could be transferred by the magnetohydrodynamic waves. The quasi-periodic variations that were observed to appear with a 97–106 min lag and to last for about 130–140 min were most likely due to the earthquake. They were transferred by the atmospheric gravity waves with a period of 7–14 min. A relative disturbance in the electron density in the atmospheric gravity wave field was observed to be approximately 5.3%. The results obtained from observations of Albanian and Turkish earthquakes show agreement. Conclusions: The magnetic variations in the 1–1000 s period range that were observed to occur before and during the earthquake have been studied.

scholarly journals Geomagnetic field fluctuations during Chuysk earthquakes on September – October, 2003

2019 ◽  
Keyword(s):  
Geomagnetic Field ◽  
Seismic Waves ◽  
Fluxgate Magnetometer ◽  
Period Range ◽  
National University ◽  
Field Fluctuations ◽  
Band Pass ◽  
S Period ◽  
Negative Links ◽  
Atmospheric Gravity

Urgency. There is an urgent need to study the interactions in the Earth – atmosphere – ionosphere – magnetosphere system. To identify direct and reverse, positive and negative links among the subsystems, sources producing massive releases of energy are commonly used. In this paper, the Chuysk earthquakes whose Richter magnitudes vary from 4.5 to 7.3 are considered as such a source. The aim of this paper is to present the findings of studying a possible response of the geomagnetic field in the 1 – 1000-s period variations to the preparation and occurrence of the Chuysk earthquakes of September – October 2003. Techniques and Methodology. The measurements were carried out using the fluxgate magnetometer located at the V. N. Karazin Kharkiv National University Geomagnetic Observatory. The sensitivity of the magnetometer is 0.5 – 500 pT in the 1 – 1000-s period range. The data processing was performed in three stages. First, the signals from the magnetometer, recorded in relative magnetometer units, were converted into absolute units, taking into account the magnetometer frequency response. Second, band-pass filtering was performed in the 1 – 10-s, 10 – 100-s, and 100 – 1000-s period ranges. Third, a system spectral analysis of time variations in the H- and D-components of the geomagnetic field was undertaken. Results: Forty three minutes and one-hundred-sixty-three minutes prior to the earthquake of Richter magnitude 7.3, quasi-periodic variations of the geomagnetic field were observed. These variations may be an earthquake magnetic precursor, and the mechanism of such a precursor has been described. After the earthquakes of Richter magnitudes 7.3, 6.7, and 7.0, quasi-periodic variations of the geomagnetic field were detected. Such variations may be caused by the perturbation transfer due to seismic waves with speeds in the 1.9 – 5.3-km/s range and owing to atmospheric gravity waves traveling with speeds in the 320- to 670-m/s range. On October 1, 2003, the changes in the character of the variations occurred with time delays of 0 to 5 min. If these variations were associated with earthquakes, the magnetohydrodynamic waves could act as an agent that transferred the disturbances. Conclusions: The moderate earthquakes are determined to be able to cause geomagnetic field disturbances recordable at distances of about 3,500 km from the epicenter.

Reflection of high-frequency radio waves in inhomogeneous ionospheric layers

Radio Science ◽  
1985 ◽  
Vol 20 (3) ◽  
pp. 303-309 ◽  
Author(s):  
Kenneth Davies ◽  
Charles M. Rush
Keyword(s):  
High Frequency ◽  
Radio Waves

scholarly journals Sensing Framework for the Internet of Actors in the Value Co-Creation Process with a Beacon-Attachable Indoor Positioning System

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 83
Author(s):  
Keiichi Zempo ◽  
Taiga Arai ◽  
Takuya Aoki ◽  
Yukihiko Okada
Keyword(s):  
Radio Wave ◽  
Indoor Positioning ◽  
Measurement Range ◽  
Pulse Interval ◽  
Retail Stores ◽  
Positioning System ◽  
Radio Waves ◽  
Positioning Systems ◽  
Environment Recognition ◽  
Indoor Positioning System

To evaluate and improve the value of a service, it is important to measure not only the outcomes, but also the process of the service. Value co-creation (VCC) is not limited to outcomes, especially in interpersonal services based on interactions between actors. In this paper, a sensing framework for a VCC process in retail stores is proposed by improving an environment recognition based indoor positioning system with high positioning performance in a metal shelf environment. The conventional indoor positioning systems use radio waves; therefore, errors are caused by reflection, absorption, and interference from metal shelves. An improvement in positioning performance was achieved in the proposed method by using an IR (infrared) slit and IR light, which avoids such errors. The system was designed to recognize many and unspecified people based on the environment recognition method that the receivers had installed, in the service environment. In addition, sensor networking was also conducted by adding a function to transmit payload and identification simultaneously to the beacons that were attached to positioning objects. The effectiveness of the proposed method was verified by installing it not only in an experimental environment with ideal conditions, but posteriorly, the system was tested in real conditions, in a retail store. In our experimental setup, in a comparison with equal element numbers, positioning identification was possible within an error of 96.2 mm in a static environment in contrast to the radio wave based method where an average positioning error of approximately 648 mm was measured using the radio wave based method (Bluetooth low-energy fingerprinting technique). Moreover, when multiple beacons were used simultaneously in our system within the measurement range of one receiver, the appropriate setting of the pulse interval and jitter rate was implemented by simulation. Additionally, it was confirmed that, in a real scenario, it is possible to measure the changes in movement and positional relationships between people. This result shows the feasibility of measuring and evaluating the VCC process in retail stores, although it was difficult to measure the interaction between actors.

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