Electromagnetic Waves Research Articles

Ultrawide Spectra Camouflage Coatings from Metallic Flake Powder.

Ultrawide-spectra-compatible camouflage materials are imperative for military science and national security due to the continuous advancement of various sophisticated multispectral detectors. However, ultrawide spectra camouflage still has challenges, as the spectral requirements for different bands are disparate and even conflicting. This work demonstrates an ultrawide spectra camouflage material compatible with visible (VIS, 400-800 nm), infrared (IR, 3-5 and 8-14 μm), and microwave (S-Ku bands, 2-12 GHz). The carbon nanotubes adsorbed on porous anodic alumina/aluminum flake powder (CNTs@PAA/AFP) material for ultrawide spectra camouflage is composed of bioinspired porous alumina surface layers for low visible reflection and aluminum flake powder substrate for low infrared emissivity, while the surface of the porous alumina layers is loaded with carbon nanotubes for microwave absorption. Compared with previous low-emissivity materials, CNTs@PAA/AFP has omnidirectional low reflectance (Ravg = 0.29) and high gray scale (72%) in the visible band. Further, it exhibits low emissivity (ε3-5μm = 0.15 and ε8-14μm = 0.18) in the dual infrared atmospheric window, which reduces the infrared lock-on range by 59.6%/49.8% in the mid/far-infrared band at high temperatures (573 K). The infrared camouflage performance calculated from the radiation temperature of CNTs@PAA/AFP coatings is enhanced to over 65%, which is at least 4 times greater than that of its substrate. In addition, the CNTs@PAA/AFP coating achieves high microwave absorption (RLmin = -42.46 dB) and an effective absorption bandwidth (EAB = 7.43 GHz) in the microwave band (S-Ku bands) due to the enhancement of interfacial polarization and conductive losses. This study may introduce new insight and feasible methods for multispectral manipulation, electromagnetic signal processing, and thermal management via bioinspired structural design and fabrication.

Interactions of Melanin with Electromagnetic Radiation: From Fundamentals to Applications.

Melanin, especially integumentary melanin, interacts in numerous ways with electromagnetic radiation, leading to a set of critical functions, including radiation protection, UV-protection, pigmentary and structural color productions, and thermoregulation. By harnessing these functions, melanin and melanin-like materials can be widely applied to diverse applications with extraordinary performance. Here we provide a unified overview of the melanin family (all melanin and melanin-like materials) and their interactions with the complete electromagnetic radiation spectrum (X-ray, Gamma-ray, UV, visible, near-infrared), which until now has been absent from the literature and is needed to establish a solid fundamental base to facilitate their future investigation and development. We begin by discussing the chemistries and morphologies of both natural and artificial melanin, then the fundamentals of melanin-radiation interactions, and finally the exciting new developments in high-performance melanin-based functional materials that exploit these interactions. This Review provides both a comprehensive overview and a discussion of future perspectives for each subfield of melanin that will help direct the future development of melanin from both fundamental and applied perspectives.

Induced Electromagnetic Radiation from a Charged Cloud in a Plane Gravitational Wave

Induced Electromagnetic Radiation from a Charged Cloud in a Plane Gravitational Wave

Doped Porous Carbon Spheres with Controllable Vesicle Structure: Preparation and the Effects of Pore Size on Electromagnetic Wave Absorption Properties.

This work reports on the preparation of uniform vesicle-structural carbon spheres doped with heteroatoms of N, P, and S, with the pore sizes strictly controlled by the hard templates of monodisperse submicron SiO2 spheres. The uniformly doped vesicular carbon microspheres are obtained in three steps: Stöber hydrolysis for the SiO2; in situ polymerization for the immobilization; and alkaline etching after carbonization. The size of the vesicles can be easily adjusted by regulating the particle size of the submicron SiO2 spheres, which has a significant effect on its electromagnetic wave (EMW) absorption performance. Compared with microspheres with pore sizes of 180 and 480nm, when the vesicle aperture is 327nm, with only 5.5wt.% filling load and 1.9mm thickness, the material shows the best EMW absorption behavior with the effective absorption bandwidth (EAB) covers the entire Ku band (6.32GHz) and the minimum reflection loss (RLmin) of -36.10dB, suggesting the optimized pore size of the microspheres can significantly improve the overall impedance matching of the material and achieve broadband wave absorption. This work paves the way for the enhancement of EMW absorption properties of porous material by optimizing the pore size of uniform apertures while maintaining their composition.

Leakage Proof, Flame-Retardant, and Electromagnetic Shield Wood Morphology Genetic Composite Phase Change Materials for Solar Thermal Energy Harvesting.

Phase change materials (PCMs) offer a promising solution to address the challenges posed by intermittency and fluctuations in solar thermal utilization. However, for organic solid-liquid PCMs, issues such as leakage, low thermal conductivity, lack of efficient solar-thermal media, and flammability have constrained their broad applications. Herein, we present an innovative class of versatile composite phase change materials (CPCMs) developed through a facile and environmentally friendly synthesis approach, leveraging the inherent anisotropy and unidirectional porosity of wood aerogel (nanowood) to support polyethylene glycol (PEG). The wood modification process involves the incorporation of phytic acid (PA) and MXene hybrid structure through an evaporation-induced assembly method, which could impart non-leaking PEG filling while concurrently facilitating thermal conduction, light absorption, and flame-retardant. Consequently, the as-prepared wood-based CPCMs showcase enhanced thermal conductivity (0.82 Wm-1K-1, about 4.6 times than PEG) as well as high latent heat of 135.5kJkg-1 (91.5% encapsulation) with thermal durability and stability throughout at least 200 heating and cooling cycles, featuring dramatic solar-thermal conversion efficiency up to 98.58%. In addition, with the synergistic effect of phytic acid and MXene, the flame-retardant performance of the CPCMs has been significantly enhanced, showing a self-extinguishing behavior. Moreover, the excellent electromagnetic shielding of 44.45dB was endowed to the CPCMs, relieving contemporary health hazards associated with electromagnetic waves. Overall, we capitalize on the exquisite wood cell structure with unidirectional transport inherent in the development of multifunctional CPCMs, showcasing the operational principle through a proof-of-concept prototype system.

Bandpass frequency selective surfaces with fast roll-off characteristics

We propose a bandpass frequency selective surface (FSS) with fast cut-off characteristics and low insertion loss. It consists of a compact high-frequency hybrid compression board with five metal layers, two Rogers RO4003C layers, and two F4B layers. The hierarchical fitting of equivalent circuits is utilized to analyze the FSS, which maintains angular stability for dual-polarized electromagnetic waves at incidence angles of less than 20 degrees. Under normal incidence, transmission amplitudes in the K-band exceed −0.87 dB. Furthermore, the proposed FSS achieves a roll-off rate of 87.6 dB GHz−1, which can be applied in dual-frequency observing systems for millimeter astronomy.

Improved detection of magnetic interactions in proteins based on long-lived coherences.

Living systems rely on molecular building blocks with low structural symmetry. Therefore, constituent amino acids and nucleotides yield short-lived nuclear magnetic responses to electromagnetic radiation. Magnetic signals are at the basis of molecular imaging, structure determination and interaction studies. In solution state, as the molecular weight of analytes increases, coherences with long lifetimes are needed to yield advantageous through-space magnetisation transfers. Interactions between magnetic nuclei can only be detected provided the lifetimes of spin order are sufficient. In J-coupled pairs of nuclei, long-lived coherences (LLC's) connect states with different spin-permutation symmetry. Here in, weshow sustained LLC'sin protein Lysozyme, weighing 14.3 kDa, with lifetimes twice as long as those of classical magnetisation for the aliphatic protons of glycine residues. We found for the first time that, in a protein of significant molecular weight, LLC's yield substantial through-space magnetisation transfers: spin-order transfer stemming from LLC's overcame transfers from classical coherences by factors > 2. Furthermore, in agreement with theory, the permutation symmetry of LLC-based transfers allows mapping interacting atoms in the protein structure with respect to the molecular plane of glycine residues in a stereospecific manner. These findings can extend the scope of liquid-state high-resolution biomolecular spectroscopy.

Effects of Heat Treatment on the Electromagnetic Wave Absorption Characteristics of Resorcinol Formaldehyde Silicon Dioxide Ceramic Particles

In light of the pressing environmental and health issues stemming from electromagnetic pollution, advanced electromagnetic wave absorbing materials are urgently sought to solve these problems. The present study delved into the fabrication of the resorcinol formaldehyde (RF)/SiO2 ceramic particles using the sol–gel route. From SEM images and XRD and XPS analysis, it can be seen that the RF/SiO2 ceramic particles are successfully generated after heat treatment at 1500 °C. At room temperature, the sample treated at 1500 °C exhibited a minimum reflection loss of −47.6 dB in the range of 2–18 GHz when the matching thickness was 5.5 mm, showcasing strong attenuation capabilities. Moreover, these particles demonstrated a considerable effective electromagnetic wave absorption bandwidth of 3.14 GHz, evidencing their potential for wideband electromagnetic wave absorption. The temperature adjustment played a pivotal role in achieving optimal impedance matching. When the heat treatment temperature is increased from 800 °C to 1500 °C, the dielectric properties of the material are improved, thus achieving the best impedance matching, thereby optimizing the material’s absorption properties for specific frequency ranges, which makes it possible to customize the electromagnetic wave-absorbing characteristics to meet specific requirements across a range of applications.

Reprogrammable reflection-transmission integrated coding metasurface for real-time terahertz wavefront manipulations in full-space

In recent years, there has been notable advancement in programmable metasurfaces, primarily attributed to their cost-effectiveness and capacity to manipulate electromagnetic (EM) waves. Nevertheless, a significant limitation of numerous available metasurfaces is their capability to influence wavefronts only in reflection mode or transmission mode, thus catering to only half of the spatial coverage. To the best of our knowledge and for the first time, a novel graphene-assisted reprogrammable metasurface that offers the unprecedented capability to independently and concurrently manipulate EM waves within both half-spaces has been introduced in the THz frequency band. This intelligent programmable metasurface achieves wavefront control in reflection mode, transmission mode, and the concurrent reflection-transmission mode, all within the same polarization and frequency channel. The meta-atom is constructed with two graphene sections, enabling straightforward modification of wave behavior by adjusting the chemical potential distribution within each graphene segment via an external electronic source. The proposed functionalities encompass various programmable modes, including single and dual beam control in reflection mode, dual beam control in transmission mode, simultaneous control of dual beams in reflection mode-direct transmission, and vice versa, and control of beam steering in reflection mode-dual beams in transmission mode simultaneously. The proposed metasurface is expected to be reprogrammable due to wavefront manipulation in both half-spaces separately and continuously for various applications such as imaging systems, encryption, miniaturized systems, and next-generation wireless intelligent communications.

A PVDF/MWCNTs/GO@MWCNTs/AgNWs bilayer structured composite film with ultra‐high EMI shielding and conductivity performance

AbstractElectromagnetic interference (EMI) shielding materials with easy processing, high electrical conductivity, and excellent absorption loss are urgently needed in aerospace, military stealth and portable electronic devices. In this study, a polyvinylidene fluoride/multi‐walled carbon nanotubes (PVDF/MWCNTs)‐3 wt% composite film prepared by simple solution mixing and polyethylene terephthalate (PET) nonwoven scraping method was used as the substrate, and the PVDF/MWCNTs/graphene oxide@multi‐walled carbon nanotubes (PVDF/MWCNTs/GO@MWCNTs) and PVDF/MWCNTs/GO@MWCNTs/silver nanowires (PVDF/MWCNTs/GO@MWCNTs/AgNWs) bilayer composite films were prepared by vacuum‐assisted filtration (VAF). When the amount of GO@MWCNTs was 20 mL, the conductivity of PVDF/MWCNTs/GO@MWCNTs film is 3.5 × 101 S m−1, the total EMI shielding effectiveness (EMI SET) was 15.5 dB and the EMI absorption efficiency (EMI SEA) was 10.7 dB, the specific EMI SE (SSE/T) was 539.5 dB/ dB/(cm−2 g). When the amount of AgNWs was 25 mL, the conductivity of PVDF/MWCNTs/GO@MWCNTs/AgNWs film with 0.47 mm thickness was 1.6 × 104 S m−1, the EMI SET was 69.1 dB, the EMI SEA was 61.1 dB, and the SSE/T was 2320.0 dB cm2 g−1. The results show that the absorption was played a dominant role in the EMI shielding mechanism of obtained films. The addition of GO@MWCNTs/AgNWs increases the electrical conductivity and EMI shielding performance of the film more than the addition of GO@MWCNTs. This is mainly because GO， MWCNTs and AgNWs formed a novel three‐dimensional conductive network structure inside the composite film due to their hydrogen bonding and van der Waals forces, which increases the carrier channels and promotes the interaction between the internal microcurrents and the electromagnetic waves, achieving the purpose of attenuating the electromagnetic waves. The obtained PVDF/MWCNTs/GO@MWCNTs/AgNWs film has good potential in EMI shielding in aerospace, military and electronic intelligence applications.Highlights Well‐dispersed and highly conductive GO@MWCNTs were prepared by hydrothermal synthesis. AgNWs with good conductivity and high aspect ratio were prepared. PVDF‐based bilayer composite films with novel 3D conductive network were prepared. The synergistic EMI shielding mechanism of the film is discussed.

All-dielectric achromatic hole-array metasurfaces

Metalens, an ultra-thin optical element composed of subwavelength structure, offers a new path for the development of miniaturized device imaging. Through the design of subwavelength units, arbitrary modulation of the phase, amplitude, and polarization of electromagnetic waves can be achieved. However, current metalenses generally suffer from the disadvantages of narrowband and Ohmic losses, which limits the development of high-quality imaging. In this work, using all-dielectric hole-array structure within the framework of effective medium theory, we demonstrate the achromatic focusing effect based on the basic Huygens principle. Moreover, by changing the position of the point source, this metalens can also achieve directional refraction with flexible angles. Our results provide a new solution for the practical application of miniaturized integrated high-quality imaging, and may open up avenues for constructing efficient artificial metasurface with metamaterials for energy harvesting and other wave manipulation.

VSHPIC: a particle-in-cell algorithm based on vector spherical harmonics expansion

The particle-in-cell (PIC) method has been widely used for studying plasma physics. However, fully three-dimensional PIC simulations always require huge computational resources. For problems with near azimuthal symmetry, recent work (Lifschitz et al 2009 J. Comput. Phys. 228 1803–14, Davidson et al 2015 J. Comput. Phys. 281 1063–77, Li et al 2021 Comput. Phys. Commun. 261 107784, Li et al 2022 J. Comput. Phys. 470 111599) has shown that expanding all the quantities defined on the grid in azimuthal harmonics and truncating the expansion can improve the code efficiency. In this paper, we describe a novel parallel algorithm for efficiently simulating three-dimensional near-spherical symmetry problems. Our approach expands all physical quantities in the θ and ϕ directions in spherical coordinates using vector spherical harmonics. The code is capable of simulating three-dimensional asymmetric scenarios by accurately tracking the evolution of distinct individual modes while preserving the charge conservation law. The fundamental dispersion relation of EM waves in the plasma has been obtained using VSHPIC simulation results. The code also shows a well strong scalability up to more than 1000 cores.

Pulsed radio wave as a sustainable control technology to improve indoor air quality

The need for technologies that can clean the air indoors has grown in pace with the rise in outside pollution. Maintaining interior environment adaptability requires a permanent air purification system that may be utilized to control PM2.5/10. In addition to more traditional methods of air purification, developing advanced control systems that effectively reduce PM levels sustainably is necessary. Pulsed radio waves may expedite the dry deposition of particles having aerodynamic dimensions of less than 30 µm. The charging and coagulation processes are evaluated in an indoor restricted environment. Experimental results reveal a similar pattern to the Monte Carlo models. Distribution of charge due to the nature of the charging environment increases the coagulation rate. Contained experimental testing confirms the filtering system functions as expected, corroborated by the present research. Daily average levels of PM2.5 and PM10 were lowered by between 55 and 41% according to a study done in three indoor settings using the control technology. Research conducted throughout all seasons showed that the approach was consistently efficient in reducing PM2.5/10. It was shown that PM concentrations could be lowered by around 45 percent using pulse radio wave technology, leading to this conclusion. The use of electromagnetic waves (EM waves) to eliminate air pollution has been suggested as a radical new approach. Considering the limitations of already used strategies, this is of paramount significance while considering solutions to control air pollution.

Microscopic structure of electromagnetic whistler wave damping by kineticmechanisms in hot magnetized Vlasov plasmas

Abstract Electromagnetic transverse perturbations propagating parallel to the external magnetic field in a
warm electron plasma, specifically the warm electron whistler waves, are simulated in κ distributed
electrons. The Vlasov-Maxwell phase-space continuum simulations are applied to the stable and
unstable (i.e., isotropic and anisotropic) VDFs including those with energetic tail, i.e., κ distribution.
The variation of real frequency from both numerical solution of dispersion relation and simulations
show limited sensitivity to electron temperature in low wave-number regime as compared to high
wave number regime, however the opposite holds for the imaginary frequency or the decay rate. For
large amplitude, nonlinear cases, simulated with anisotropic κ distributions the very low anisotropy
cases find the growth rate increasing with increasing the κ while this trend reverses for higher
anisotropy. The phase-space portraits of the these cases show that after the linear damping phase
of the evolution, the particles are trapped in the wave magnetic field leading to the wave amplitudes
oscillating about a mean value which follow the theoretical analysis [1].

Superscattering of electromagnetic waves from subwavelength dielectric structures

Superscattering, corresponding to the scattering cross section of a scatterer being significantly larger than its single-channel limit, has attracted increasing attention due to its huge potential for practical applications. The realization of superscattering relies on the overlapping of multiple resonance modes in a scatterer. Accordingly, superscattering phenomena have been observed primarily in alternating plasmonic/dielectric layered structures which support surface plasmons. However, such systems suffer from high Ohmic loss due to the excitation of surface plasmons, hindering broader application of the plasmonic/dielectric hybrid systems. On the other hand, subwavelength structures based on high permittivity dielectric materials (such as ferroelectric ceramics) offer expansive opportunities to realize electric and magnetic resonances at microwave and THz frequencies. Here, based on optimization methods involving mode analysis, we numerically demonstrate superscattering from individual multilayered dielectric cylinders. The maximum scattering cross section achieved is determined by the collective contributions from several resonance modes excited in a complex cylinder. Our results reveal that a combination of mode analysis and a custom optimization method can enable efficient designs of complex dielectric structures exhibiting exotic scattering responses.

Mechanical recycling process: An alternative for a viable disposal of carbon fiber‐reinforced thermoplastic waste

AbstractConcern for the environment has increased the interest of the automotive and aerospace industries in evaluating the feasibility of mechanical recycling of waste carbon‐fiber‐reinforced polymer composites (CFRP) and waste from protective films used during the transport and storage of thermosetting composites, which are removed and discarded during manufacturing. Therefore, this work aimed to develop a recyclable composite from protective film waste by incorporating carbon fiber/poly(aryl ether ketone) (CF/PAEK) composite particles obtained through grinding in knife mills, followed by an analysis of the particle size distribution. Protective film residues (PEres) were cut to facilitate processing. A mixture of low‐density polyethylene and PEres (50/50) was used as the composite matrix, and 5, 10, 15, and 20 wt% CF/PAEK composite particles were added as the reinforcing agents. Then, these recycled composites were prepared by melt mixing using a twin‐screw extruder and injection molding to obtain standardized samples. Mechanical, thermal, electrical, and electromagnetic properties were evaluated. It was possible to observe that the increase in the addition of CF/PAEK composite particles contributed to a 290% increase in elastic modulus values and a 9.1% increase in Shore D hardness, electrical conductivity, and attenuation of the electromagnetic wave. Furthermore, satisfactory adhesion between filler and matrix contributed to a good interface and reinforcement of the final material.Highlights Mechanical recycling by extrusion of waste from the automotive and aerospace sectors Grinding of carbon fiber/poly(aryl ether ketone) composite waste to be used as filler Protective film waste used as matrix Composites developed with waste with good electrical and electromagnetic properties The addition of thermoplastic composite residues does not affect thermal and mechanical properties

Effects of non-ionizing radio frequency electromagnetic radiation on the development and behavior of early embryos of Danio rerio

ABSTRACT Biological effects of radio frequency electromagnetic radiation (RF-EMR) in the range of 900–1800 MHz emerging from the mobile phone were investigated and were found to influence the locomotor pattern when exposure was initiated from 1 hour post fertilization (hpf) in zebrafish embryos (ZE), Danio rerio. Mobile phones and other wireless devices offer tremendous advantages. However, on the flipside they are leading to an increased electromagnetic energy in the environment, an excess of which could be termed as electromagnetic pollution. Herein, we tried to understand the effects of RF-EMR emerging from the mobile phone, on the development and behavior of ZE, exposed to RF-EMR (specific absorption rate of 1.13 W/kg and 1800 MHz frequency) 1 hr daily, for 5 days. To understand if there could be any developmental stage-specific vulnerability to RF-EMR, the exposure was initiated at three different time points: 1hpf, 6hpf and 24hpf of ZE development. Observations revealed no significant changes in the survival rate, morphology, oxidative stress or cortisol levels. However, statistically significant variations were observed in the batch where exposure started at 1hpf, with respect to locomotion patterns (distance travelled: 659.1 ± 173.1 mm Vs 963.5 ± 200.4 mm), which could be correlated to anxiety-like behavior; along with a corresponding increase in yolk consumption (yolk sac area: 0.251 ± 0.019 mm2 Vs 0.225 ± 0.018 mm2). Therefore, we conclude that RF-EMR exposure influences the organism maximally during the earliest stage of development, and we also believe that an increase in the time of exposure (corresponding to the patterns of current usage of mobile phones) might reveal added afflictions.

Interacting supernovae as high-energy multimessenger transients

Multiwavelength observations have revealed that dense, confined circumstellar material (CCSM) commonly exists in the vicinity of supernova (SN) progenitors, suggesting enhanced mass losses years to centuries before their core collapse. Interacting SNe, which are powered or aided by interaction with the CCSM, are considered to be promising high-energy multimessenger transient sources. We present detailed results of broadband electromagnetic emission, following the time-dependent model proposed in the previous work on high-energy SN neutrinos [K. Murase, New prospects for detecting high-energy neutrinos from nearby supernovae, ]. We investigate electromagnetic cascades in the presence of Coulomb losses, including inverse-Compton and synchrotron components that significantly contribute to MeV and high-frequency radio bands, respectively. We also discuss the application to SN 2023ixf. Published by the American Physical Society 2024

Surfactant-induced morphology engineering in chitosan-derived carbon aerogels realizing high-efficiency absorption of electromagnetic wave

Despite the significant research advances in dielectric loss-type absorbents, developing high-efficiency electromagnetic wave (EMW) absorbents dominated by the conduction loss are still challenging due to the imbalance between impedance matching and conduction loss. In this study, for the first time, high-efficiency EMW absorption governed by the conduction loss in chitosan-derived carbon aerogels was realized through surfactant-assisted morphology modification. Electrostatic interaction and hydrogen bonding between chitosan and surfactants were ingeniously applied to induce tightly-stacked nanosheets to transform into three-dimensional (3D) interwork structure and loosely-stacked porous nanosheets, respectively, and thus the moderately enhanced conductivity converted the original EMW-transparent carbon to EMW-absorbing carbon. Benefiting from the favorable balance of impedance matching and conduction loss, the carbon aerogels with 3D interwork structure showed a broad effective absorption bandwidth (EAB) of 7.2 GHz (2.8 mm) and minimum reflection loss (RLmin) of −42.6 dB; and moreover, an ultra-wide EAB of 7.84 GHz at 2.9 mm occurred in the samples with loosen and wrinkled nanosheet structure, both outperforming most of reported carbon-based composite aerogels. This work provides a new insight for the morphology regulation and performance optimization of carbonaceous EMW absorbents.

Earthquakes Three-Stage Early Warning and Short-Term Prediction

Among the anomalous geophysical phenomena observed preceding earthquakes, specific attention has been given to VLF/LF, ULF (very low frequency/low frequency, ultra-low frequency) electromagnetic (EM) emissions, recorded before earthquakes, because of an interesting correlation between them and seismic activity. Numerous scientific papers have been published on this topic, providing convincing evidence of these processes observed using ground-based and satellite ground-based observations during the preparation for the earthquake. These phenomena are detectable both at laboratory and geological scales. The authors of this paper have used an avalanche-like unstable geological model of fault formation and a model of the generation of electromagnetic emissions detected before the earthquakes to prove the prediction capabilities of VLF/LF EM emissions. The first gives a clear imagination of earthquake preparation in all stages in the focal area from the beginning of the micro-cracks appearing to the final formation of fault. Another one, based on electrodynamics, explains the EM emissions origination process and offers a formula that analytically connects the observed frequency of EM radiation with the linear size of the emitted body (fault). It is worth emphasizing the synthesis and rather harmonious relation of the mentioned models. Based on the above models conducted studies clearly show that the description of a qualitative avalanche-unstable geological model of fault formation using VLF/LF EM radiation data made it possible to quantitatively characterize the full cycle of preparation and occurrence of earthquake process. Namely, in the case of VLF/LF emissions monitoring, the beginning of the “avalanche process” of ruptures is considered the first stage of early warning of an incoming earthquake. The so-called EM emissions “silence” period is assessed as the second stage of early warning. The third early warning or an alarm about an incoming earthquake may be announced immediately at the moment of the first anomaly appearance subsequently the “silence” period. This article offers the method of earthquake three-step early warning and short-term (hourly) prediction.