scholarly journals Review of pulse impacts on the magnetospheric oscillations

2015 ◽  
Vol 1 (4) ◽  
pp. 72-81
Author(s):  
Анатолий Гульельми ◽  
Anatol Guglielmi ◽  
Александр Потапов ◽  
Alexander Potapov ◽  
Борис Довбня ◽  
...  
Keyword(s):  
Practical Importance ◽  
Low Frequency ◽  
Oscillatory System ◽  
Interplanetary Shock ◽  
Space Physics ◽  
Near Earth Space ◽  
Oscillatory Systems ◽  
Impulse Action ◽  
Geomagnetic Tail ◽  
Interplanetary Shock Wave

Response of magnetospheric oscillatory systems in the ultra-low-frequency (ULF) range on electromagnetic, mechanical, thermal, and chemical impulse action are overviewed and selectively analyzed. Impulses can occur both inside the magnetosphere (e.g. explosion in the geomagnetic tail, impulsive injection of energetic particles) and outside (e.g. solar flare, interplanetary shock wave, thunderstorm discharge, earthquake, volcanic eruption etc.). We suggest systematics of impulses which is based on geophysics and space physics data and is closely related to the theory of ULF oscillations. The systematics is of cognitive and practical importance, and it allows us to interpret a rich variety of responses of the magnetosphere to impulses of the terrestrial and space origins. The classification principle is selected according to which an impulse type is determined from two criteria such as impulse origin location and character of impulse action on one or another oscillatory system of the magnetosphere. The primary conditions for completeness and validity of division are fulfilled because all possible terms of putting impulses to classes, types and forms are specified, and the terms do not overlap. The classification and introduced nomenclature are helpful because they make possible to systematize common properties and specific features of types and forms of impulses. This is especially important with regard to reaction of the Earth’s plasma sheaths to impulses generated during an earthquake preparation as well as under experimental study of dynamic processes in the near-Earth space. The examples of response of ULF oscillations to impulsive actions are shown. The particular focus is given to review of studies which still are not mentioned in reviews and monographies.

scholarly journals Very-Low-Frequency transmitters bifurcate energetic electron belt in near-earth space

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Man Hua ◽  
Wen Li ◽  
Binbin Ni ◽  
Qianli Ma ◽  
Alex Green ◽  
...  
Keyword(s):  
Practical Importance ◽  
Energetic Electron ◽  
Low Frequency ◽  
Radiation Environment ◽  
Particle Radiation ◽  
Earth Space ◽  
Quantitative Evidence ◽  
Very Low Frequency ◽  
Near Earth Space ◽  
Submarine Communications

Abstract Very-Low-Frequency (VLF) transmitters operate worldwide mostly at frequencies of 10–30 kilohertz for submarine communications. While it has been of intense scientific interest and practical importance to understand whether VLF transmitters can affect the natural environment of charged energetic particles, for decades there remained little direct observational evidence that revealed the effects of these VLF transmitters in geospace. Here we report a radially bifurcated electron belt formation at energies of tens of kiloelectron volts (keV) at altitudes of ~0.8–1.5 Earth radii on timescales over 10 days. Using Fokker-Planck diffusion simulations, we provide quantitative evidence that VLF transmitter emissions that leak from the Earth-ionosphere waveguide are primarily responsible for bifurcating the energetic electron belt, which typically exhibits a single-peak radial structure in near-Earth space. Since energetic electrons pose a potential danger to satellite operations, our findings demonstrate the feasibility of mitigation of natural particle radiation environment.

scholarly journals SUBSTANTIATION OF RATIONAL SELECTION OF MOTOR-VIBRATORS VIBRATION MACHINES

2019 ◽  
pp. 24-32
Author(s):  
Oleksii Lanets ◽  
Volodymyr Borovets ◽  
Pavlo Maistruk ◽  
Iryna Derevenko
Keyword(s):  
Significant Proportion ◽  
Low Frequency ◽  
Oscillatory System ◽  
Analytical Relation ◽  
Technological Parameters ◽  
Drive Power ◽  
Oscillatory Systems ◽  
Inertial Parameters ◽  
The Masses ◽  
Analytical Expressions

An integral component in the calculation of vibration machines is the establishment of drive power necessary to set in motion an oscillating system with specified characteristics. However, difficulties often arise at this stage. The inertial characteristics of the drive directly affect the power consumption. Therefore, when calculating it, you must already know the size of the drive, which is still unknown, since it is only being installed. This question is especially relevant for low-frequency oscillatory systems with an inertial drive, in which the inertial parameters of the drive are proportional to the masses of the oscillatory systems. In such oscillatory systems, ignoring the mass of the drive when setting the consumed power to set the mechanical oscillating system in motion can lead to the fact that the vibrating machine will not be able to provide the expected (calculated) technical and technological parameters, since the massive drive oscillates with the whole system, will take on its own propulsion a significant proportion of the energy. The article justifies the analytical relation¬ships for calculating the power of vibration machines with inertial drive, taking into account the mass of vibrator motors. For this, systems of equations are solved that interconnect analytical expressions for calculating the powers necessary to bring the oscillatory systems into motion, taking into account the mass of vibrator motors. The solution to such systems is the value of the required drive power (vibrator motors) and its mass, which is already consistent with the masses of unified vibrator motors produced by manufacturers. The obtained analytical dependences make it quite easy to determine the power of the drives in one-, two- and trimass oscillation systems of vibration machines with an inertial drive. Using the formulas obtained in the article, it is possible to precisely establish the necessary drive power to set the oscillatory system in motion and uniquely select the mass of the vibrator motor.

MULTI–INERT OSCILLATORY MECHANISM

2020 ◽  
Vol 2 ◽  
pp. 19-25
Author(s):  
I.P. POPOV
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Oscillation Frequency ◽  
Free Oscillation ◽  
Initial Conditions ◽  
Oscillatory System ◽  
Harmonic Oscillations ◽  
Oscillatory Systems ◽  
Oscillatory Mechanism ◽  
Mutual Conversion

A mechanical oscillatory system with homogeneous elements, namely, with n massive loads (multi– inert oscillator), is considered. The possibility of the appearance of free harmonic oscillations of loads in such a system is shown. Unlike the classical spring pendulum, the oscillations of which are due to the mutual conversion of the kinetic energy of the load into the potential energy of the spring, in a multi–inert oscillator, the oscillations are due to the mutual conversion of only the kinetic energies of the goods. In this case, the acceleration of some loads occurs due to the braking of others. A feature of the multi–inert oscillator is that its free oscillation frequency is not fixed and is determined mainly by the initial conditions. This feature can be very useful for technical applications, for example, for self–neutralization of mechanical reactive (inertial) power in oscillatory systems.

scholarly journals TOTAL ENERGY OF HARMONIC OSCILLATOR WITH IMPULSE ACTION

2020 ◽  
pp. 56-59
Author(s):  
K. Elgondiyev ◽  
S. Matmuratova ◽  
V. Borodin ◽  
L. Vovk
Keyword(s):  
Periodic Function ◽  
Harmonic Oscillator ◽  
Total Energy ◽  
Homogeneous Equation ◽  
External Perturbation ◽  
Oscillatory System ◽  
Time Variable ◽  
Harmonic Oscillations ◽  
Impulse Action ◽  
Periodic Impulse

The problem of finding the total energy of a harmonic oscillator with pulsed action at fixed moments of time is considered. Both for the case of the homogeneous equation of harmonic oscillations and for the case of the equation of harmonic oscillations in the presence of external perturbation, formulas for the total energy of the oscillatory system are obtained. The case of periodic impulse effects is analyzed. The conditions under which in this oscillatory system there are periodic modes are specified. It is shown that under the fulfillment of these conditions on the values of impulse action and external perturbation, the total energy of the vibrational system is also a periodic function of the time variable.

scholarly journals Estimation of Delay Times in Coupling Between Autonomic Regulatory Loops of Human Heart Rate and Blood Flow Using Phase Dynamics Analysis

2017 ◽  
Vol 9 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Vladimir S Khorev ◽  
Anatoly S Karavaev ◽  
Elena E Lapsheva ◽  
Tatyana A Galushko ◽  
Mikhail D Prokhorov ◽  
...  
Keyword(s):  
Heart Rate ◽  
Delay Time ◽  
Healthy Subjects ◽  
Low Frequency ◽  
Phase Dynamics ◽  
Oscillatory Systems ◽  
Low Frequency Oscillations ◽  
Delay Times ◽  
The Difference ◽  
Regulatory Loop

Objective: We assessed the delay times in the interaction between the autonomic regulatory loop of Heart Rate Variability (HRV) and autonomic regulatory loop of photoplethysmographic waveform variability (PPGV), showing low-frequency oscillations. Material and Methods: In eight healthy subjects aged 25–30 years (3 male, 5 female), we studied at rest (in a supine position) the simultaneously recorded two-hour signals of RR intervals (RRIs) chain and finger photoplethysmogram (PPG). To extract the low-frequency components of RRIs and PPG signal, associated with the low-frequency oscillations in HRV and PPGV with a frequency of about 0.1 Hz, we filtered RRIs and PPG with a bandpass 0.05-0.15 Hz filter. We used a method for the detection of coupling between oscillatory systems, based on the construction of predictive models of instantaneous phase dynamics, for the estimation of delay times in the interaction between the studied regulatory loops. Results: Averaged value of delay time in coupling from the regulatory loop of HRV to the loop of PPGV was 0.9±0.4 seconds (mean ± standard error of the means) and averaged value of delay time in coupling from PPGV to HRV was 4.1±1.1 seconds. Conclusion: Analysis of two-hour experimental time series of healthy subjects revealed the presence of delay times in the interaction between regulatory loops of HRV and PPGV. Estimated delay time in coupling regulatory loops from HRV to PPGV was about one second or even less, while the delay time in coupling from PPGV to HRV was about several seconds. The difference in delay times is explained by the fact that PPGV to HRV response is mediated through the autonomic nervous system (baroreflex), while the HRV to PPGV response is mediated mechanically via cardiac output.

scholarly journals MHD-waves in the geomagnetic tail: A review

10.12737/7168 ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 4-22 ◽  
Author(s):  
Анатолий Леонович ◽  
Anatoliy Leonovich ◽  
Виталий Мазур ◽  
Vitaliy Mazur ◽  
Даниил Козлов ◽  
...  
Keyword(s):  
Numerical Models ◽  
Experimental Studies ◽  
Low Frequency ◽  
Detailed Comparison ◽  
Mhd Waves ◽  
Theoretical Studies ◽  
Geomagnetic Tail ◽  
Magnetopause Oscillations ◽  
Experimental And Theoretical Studies ◽  
Theoretical Results

This article presents the review of experimental and theoretical studies on ultra-low-frequency MHD oscillations of the geomagnetic tail. We consider the Kelvin–Helmholtz instability at the magnetopause, oscillations with a discrete spectrum in the “magic frequencies” range, the ballooning instability of coupled Alfvén and slow magnetosonic waves, and “flapping” oscillations of the current sheet of the geomagnetic tail. Over the last decade, observations from THEMIS, CLUSTER and Double Star satellites have been of great importance for experimental studies. The use of several spacecraft allows us to study the structure of MHD oscillations with high spatial resolution. Due to this, we can make a detailed comparison between theoretical results and those obtained from multi-spacecraft studies. To make such comparisons in theoretical studies, in turn, we have to use the numerical models closest to the real magnetosphere.

scholarly journals Alternating (AC) Loop Current Attacks Against the KLJN Secure Key Exchange Scheme

2021 ◽  
pp. 2150050
Author(s):  
Mutaz Y. Melhem ◽  
Christiana Chamon ◽  
Shahriar Ferdous ◽  
Laszlo B. Kish
Keyword(s):  
Electromagnetic Interference ◽  
High Frequency ◽  
Practical Importance ◽  
Low Frequency ◽  
Key Exchange ◽  
Power Density Spectrum ◽  
Voltage Source ◽  
Loop Current ◽  
Johnson Noise ◽  
Density Spectrum

Recently, several passive and active attack methods have been proposed against the Kirchhoff–Law–Johnson–Noise (KLJN) secure key exchange scheme by utilizing direct (DC) loop currents. The DC current attacks are relatively easy, but their practical importance is low. On the other hand, parasitic alternating (AC) currents are virtually omnipresent in wire-based systems. Such situations exist due to AC ground loops and electromagnetic interference (EMI). However, utilizing AC currents for attacks is a harder problem. Here, we introduce and demonstrate AC current attacks in various frequency ranges. The attacks exploit a parasitic/periodic AC voltage-source at either Alice’s or Bob’s end. In the low-frequency case, the procedure is the generalized form of the former DC ground-loop-based attack. In the high-frequency case, the power density spectrum of the wire voltage is utilized. The attack is demonstrated in both the low and the high-frequency situations. Defense protocols against the attack are also discussed.

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