Plasma Waves Research Articles

Modulation Instability and Dynamical Analysis of New Abundant Closed‐Form Solutions of the Modified Korteweg–de Vries–Zakharov–Kuznetsov Model With Truncated M‐Fractional Derivative

In this work, we study the modulation instability (MI) and closed‐form soliton solution of the modified Korteweg–de Vries–Zakharov–Kuznetsov (mKdV‐ZK) equation with a truncated M‐fractional derivative. The mKdV‐ZK equation can be used to describe the behavior of ion‐acoustic waves in plasma and the propagation of surface waves in deep water with nonlinear and dispersive effects in fluid dynamics. To execute a closed soliton solution, we implement two dominant techniques, namely, the improved F‐expansion scheme and unified solver techniques for the mKdV‐ZK equation. Under the condition of parameters, the obtained solutions exhibit hyperbolic, trigonometric, and rational functions with free parameters. Using the Maple software, we present three‐dimensional (3D) plots with density plots and two‐dimensional (2D) graphical representations for appropriate values of the free parameters. Under the conditions of the numerical values of the free parameters, the obtained closed‐form solutions provided some novel phenomena such as antikink shape wave, dark bell shape, collision of kink and periodic lump wave, periodic wave, collision of antikink and periodic lump wave, collision of linked lump wave with kink shape, periodic lump wave by using improved F‐expansion method and kink shape, diverse type of periodic wave, singular soliton, and bright bell and dark bell‐shape wave phenomena by using unified solver method. The comparative effects of the fractional derivative are illustrated in 2D plots. We also provided a comparison between the results obtained through the suggested scheme and those obtained by other approaches, showing some similar solutions and some that are different. Besides, to check of stability and instability of the solution, the MI analysis of the given system is investigated based on the standard linear stability analysis and the MI gain spectrum analysis. With the use of symbolic calculations, the applied approach is clear, simple, and elementary, as demonstrated by the more broad and novel results that are obtained. It may also be applied to more complex phenomena.

Field Modulations of Ion Acoustic Waves in Plasma With Vasyliunas–Schamel Distributed Electrons

Field Modulations of Ion Acoustic Waves in Plasma With Vasyliunas–Schamel Distributed Electrons

Reliable analysis for obtaining exact soliton solutions of (2+1)-dimensional Chaffee-Infante equation

<abstract><p>The (2+1)-dimensional Chaffee-Infante equation (CIE) is a significant model of the ion-acoustic waves in plasma. The primary objective of this paper was to establish and examine closed-form soliton solutions to the CIE using the modified extended direct algebraic method (m-EDAM), a mathematical technique. By using a variable transformation to convert CIE into a nonlinear ordinary differential equation (NODE), which was then reduced to a system of nonlinear algebraic equations with the assumption of a closed-form solution, the strategic m-EDAM was implemented. When the resulting problem was solved using the Maple tool, many soliton solutions in the shapes of rational, exponential, trigonometric, and hyperbolic functions were produced. By using illustrated 3D and density plots to evaluate several soliton solutions for the provided definite values of the parameters, it was possible to determine if the soliton solutions produced for CIE are cuspon or kink solitons. Additionally, it has been shown that the m-EDAM is a robust, useful, and user-friendly instrument that provides extra generic wave solutions for nonlinear models in mathematical physics and engineering.</p></abstract>

On the possibility of mode coupling for low frequency electromagnetic waves in plasmas with anisotropy of temperature

We study the dispersion relation for low frequency electromagnetic waves propagating along the ambient magnetic field and investigate the possibility of occurrence of coupling between waves in the ion cyclotron branch and waves in the whistler branch. The results obtained show that the coupling may occur in the case of conditions leading to the ion cyclotron instability, for sufficiently high value of the ratio between perpendicular and parallel ion temperature, and does not occur in the case of conditions leading to the ion firehose instability. The results also show that the decrease in the value of the plasma beta may lead to the disappearance of the mode coupling conditions. Regarding the effect of the electron population, it is shown that the change in the shape of the electron velocity distribution, from Maxwellian to bi-Kappa form, does not change the results obtained, as long as the electron temperatures are isotropic, but the increase in anisotropy in the electron temperatures may lead to the disappearance of the coupling between the different waves. The consequences of the frequency dependency of the mode coupling conditions are discussed considering wave propagation in an inhomogeneous medium, leading to the conclusion that the energy of a packet of waves of a given mode can be absorbed or mode converted over an extended region of space. These findings can be of relevance for the analysis and understanding of processes related to the conversion between ion cyclotron waves and whistler waves.

Wavefront distortion and compensation for weakly relativistic vortex beams propagating in plasma

The propagation of electromagnetic wave in plasma is one of the long-standing concerns in the field of laser plasma, and it is closely related to the researches of radiation source generation, particle acceleration, and inertial confinement fusion. Recently, the proposal of various schemes for generating intense vortex beams has led to an increasing number of researchers focusing on the interaction between intense vortex beams and plasmas, resulting in significant research progress in various areas, such as particle acceleration, high-order harmonic generation, quasi-static self-generated magnetic fields, and parametric instability. Compared with traditional Gaussian beams, vortex beams, featuring their hollow amplitudes and helical phases, can exhibit novel phenomena during propagating through plasma. In this work, we primarily focus on studying the influence of the propagation process on the wave structure of vortex beams before filamentation occurs. The three-dimensional particle-in-cell simulations show that weakly relativistic vortex beams exhibit wavefront distortion during their propagation in plasma. The distortion degree is closely related to the intensity of the electromagnetic wave and the propagation distance for a given plasma density. This phenomenon is theoretically explained by using a phase correction model that considers the relativistic mass correction of electrons. Additionally, we demonstrate that the wavefront distortion can be compensated for and suppressed by appropriately modulating the initial plasma density, as confirmed by three-dimensional particle simulations. The results of decomposing the wavefront into Laguerre-Gaussian (LG) mode components indicate that the wavefront distortion is primarily caused by high-order <i>p</i> LG modes, and it is independent of other <i>l</i> LG modes. Additionally, we extend the present investigation to the propagation of vortex beams in axially magnetized plasma, where the phase correction model can also effectively explain the occurrence of wavefront distortion. Our work can deepen the understanding of the interaction between plasma and strong vortex beams, and provide some valuable references for designing plasma devices serving as the manipulation of intense vortex beams in future research.

Elasto‐Thermodiffusion Modeling Using Optoelectronic Microtemperature Processes for a Ramp‐Type Heating Nano‐Semiconductor Material

The theory of photo‐thermoelasticity describes how heating or elastic microstructure mechanical deformation can modify a material’s optical‐thermal properties. This theory particularly highlights the effect of microtemperature on elasticity and efficient heat transport. This work provides a new theoretical framework for thermooptical elastic materials and clarifies the relationship between thermomechanical and plasma waves in microtemperature‐affected semiconductors such as silicon. The model focuses on studying the elasto‐thermodiffusion (ETD) theory’s electron‐hole interaction. Microtemperature effects during photothermal (PT) stimulation are studied in this theory. In one‐dimensional (1D) settings, the Laplace transform is utilized which can be solved using the governing equations for thermoelastic (TD) processes and electronic (ED) deformation processes in a nondimensional form. The proposed model is put to use in analyzing how ramp‐type heating affects an unbounded semiconductor material plane at rest. The discussion section presents a series of graphs to analyze the effect of the main parameters.

The Efficient Method to Solve the Conformable Time Fractional Benney Equation

The current study employed the innovative conformable fractional method to analyze the nonlinear Benney equations involving the conformable fractional derivative. Conformable fractional Benney equations have been examined by the conformable q‐Shehu analysis transform method. By including nonlinear factors, it offers a more precise depiction of wave propagation compared to linear models. Various natural phenomena, including ocean waves, plasma waves, and some forms of solitons, display nonlinear behavior that cannot be precisely explained by linear equations. The fractional Benney equation is important because it extends the classical Benney equation, which describes the evolution of weakly nonlinear and weakly dispersive long waves in shallow water. By incorporating fractional calculus operators, the fractional Benney equation provides a more accurate description of wave propagation phenomena in certain physical systems characterized by nonlocal or memory‐dependent behavior. The utilization of the Benney equation enables researchers to simulate these occurrences with greater realism. This study investigates the convergence and inaccuracy of the future scheme. The conformable q‐Shehu homotopy analysis transform method (Cq‐SHATM) generates h‐curves that demonstrate the convergence interval of the series solution obtained. In order to determine the effectiveness and suitability of the Cq‐SHATM, uniqueness and convergence theorems have been proven. This study presents an application that showcases the potential advantages and efficacy of the suggested method. Moreover, an error analysis is conducted to validate the precision of the scheme. Computational simulations are performed to verify the accuracy of the upcoming method. This study presents the results gained from the numerical and graphical analysis. The method presented in this work demonstrates a high level of computational accuracy and simplicity in analyzing and solving complex phenomena associated with conformable fractional nonlinear partial differential equations in the fields of science and technology.

Higher Order Corrections to Kinetic Alfvén Waves in Nonthermal Plasma

Higher Order Corrections to Kinetic Alfvén Waves in Nonthermal Plasma

ВОЛНЫ В СРЕДЕ ВЯЗКОСТНОЙ КВАРК-ГЛЮОННОЙ ПЛАЗМЫ

Since quark-gluon plasma was discovered, it has been called the new state of matter, prompting the beginning of the study of collective effects. Continuing this topic, the oscillation modes of internal waves in a quark-gluon plasma have been investigated. The medium of a quark-gluon plasma is considered an ideal fluid with a small viscosity. The viscosity is taken into account using a dielectric function with a viscosity parameter, which is related to the entropy, and this parameter can be chosen in accordance with different theoretical approaches to describing a quark-gluon plasma. The problem was solved in the long-wavelength limit, but this solution corresponds to the physical case described in the article. This approach reduces the problem to non-linear algebraic equations that were solved using software for numerical calculations. For illustration, the oscillation modes of a viscous quark-gluon plasma are compared with the oscillation modes of a collisional quark-gluon plasma - this will show the effect of the parameter of the dielectric function, which takes into account only viscosity. The solutions are presented in the form of graphs of frequency versus wavenumber, in which you can clearly see the oscillatory waves. Also, these vibrational modes can be used to judge the nature of the waves, and for physical interpretation.

Formation of fast-ignition hotspots and propagartion of burning waves in pre-compressed isochoric plasmas

The formation and evolution of hotspots is important for achieving ignition and high energy gain in inertial fusion process. However, most of relevant studies are carried out on pre-compressed plasmas with an isobaric configuration, the evolution of the hotspot in a plasma with an isochoric configuration is rarely studied. In this paper, a semi-analytical model is developed to describe the evolution of the hotspot boundary and propagation of fusion burning waves for a high-density pre-compressed plasma with an isochoric configuration in the double-cone ignition scheme. For the shock wave, the strong shock wave approximation and the quasi-isobaric approximation are reasonable. The quasi-isobaric approximation shows that as the plasma density behind the shock wave increases, the plasma temperature decreases. Because of these, the range of <inline-formula><tex-math id="M4">\begin{document}$ {\mathrm{\alpha }} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M4.png"/></alternatives></inline-formula>-particles decreases rapidly behind the shock wave, forming an <inline-formula><tex-math id="M5">\begin{document}$ {\mathrm{\alpha }} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M5.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M5.png"/></alternatives></inline-formula>-particle absorption peak. Therefore, considering that the hotspot is the main region where <inline-formula><tex-math id="M6">\begin{document}$ {\mathrm{\alpha }} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M6.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M6.png"/></alternatives></inline-formula>-particles are produced and deposited, the position of the shock peak can be used to identify the boundary of the hotspot in a high-density plasma with an isochoric configuration. It also shows that a “self-regulating burning process” exists in the burning process of the isochoric hotspot, most of <inline-formula><tex-math id="M7">\begin{document}$ {\mathrm{\alpha }} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M7.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M7.png"/></alternatives></inline-formula>-particles are deposited in the stable region and behind the shock, and finally, transport through the shock peak and heat the cold fuel, resulting in the temperature rising. In the high-density hotspots of plasma with an isochoric configuration, the deposition of α-particles behaves as an obvious non-uniform distribution effect. By analyzing the non-uniform deposition of α-particles, the deposition rate of α-particles at the edge of spherical uniform hotspot is calculated, then the temperature and density evolution of the isochoric hotspot can be well described. The model can be used to estimate the Lawson parameter of the hotspots at the end of the early stage of ignition. It is found that a lower fast electron energy is more beneficial to ignition and high gain operation of fusion plasma. It is also shown that the high density of the hotspots in the isochoric plasma will lead to a higher fusion burning rate, which can offset the negative influence of the shock wave and even achieve higher energy gain. The semi-analytical model is verified by the hydrodynamic simulations of O-SUKI-N.

Varieties of Nonlinear Ion-Acoustic Waves in Superthermal Plasma Within Titan’s Ionosphere

Varieties of Nonlinear Ion-Acoustic Waves in Superthermal Plasma Within Titan’s Ionosphere

Shock electrostatic electron acoustic wave features in four-component electron–positron plasma

The linear (nonlinear) wave properties of dissipative electron acoustic plasma have been studied. The impacts of temperatures and densities on the properties of linear real and imaginary (growth rate) plasma frequencies have been examined. The effects of viscosities in the linear growth rate are also studied. Accordingly, the significant shock-like electrostatic field in auroral plasmas has been discussed. Furthermore, the electrostatic dissipative fields have been studied to explain experimental observations. A comparison between the obtained electrostatic dissipative fields and satellite observations in auroral plasmas is briefly discussed.

Solitary waves of the generalized Zakharov equations via integration algorithms

<abstract><p>In many applications, the investigation of traveling wave solutions is essential in obtaining an accurate description of the dynamical behavior of most physical phenomena. The exact solutions to nonlinear equations can provide more physical descriptions and insightful details for many problems of practical interest. This paper focuses on investigating the solitary wave solutions of the generalized Zakharov equations (GZEs) by using four integration algorithms, namely, the modified $ (g'/g^{2}) $-expansion method, the modified $ (g') $-expansion method, the generalized simple ($ w/g $)-expansion method, and the addendum to Kudryashov's method. The GZEs have been widely used to describe the propagation of Langmuir waves in the field of plasma physics. The efficiency and simplicity of these methods are evaluated based on their application to GZEs, which have yielded multiple new optical solitary wave solutions in the form of rational, trigonometric, and hyperbolic functions. By using a suitable wave transformation, the coupled nonlinear partial differential equations are converted into ordinary differential equations. The derived optical solutions are graphically depicted in $ 2 $D and $ 3 $D plots for some specific parameter values. The traveling wave solutions discovered in the current study constitute just one example of the desired solutions that may enable the exploration of the physical properties of many complex systems and could also contribute greatly to improving our understanding of many interesting natural phenomena that arise in different applications, including plasma physics, fluid mechanics, protein chemistry, wave propagation, and optical fibers.</p></abstract>

Является ли аутоплазма, обогащенная тромбоцитарными факторами роста, и экстракорпоральная ударно-волновая терапия новым рубежом в лечении пациентов с эректильной дисфункцией?

Background. Existing methods for treating erectile dysfunction (ED) do not always provide the necessary therapeutic effect and/or may not be recommended for certain patients. Aim. Evaluate the effectiveness of correcting erectile dysfunction using platelet-rich plasma (PRP) and extracorporeal shock wave therapy (ESWT). Material and methods. 100 men were randomly assigned to 3 groups. Group 1 (n=20) received ESWT treatment on the penis twice a week for 6 weeks. Group 2 (n=40) and Group 3 (n=40) had two visits per week for 6 weeks, involving both ESWT and PRP injections into the penis. In Group 2, PRP activation was performed using ESWT, while in Group 3, it was done using a 10% solution of CaCl2. Patients were evaluated at 0 and 60 days of the study, assessing IIEF-5, SEP, EHS, GAQ, blood testosterone levels, and penile Doppler ultrasound with PGE1. Results. In group 1 IIEF-5 improved from 14.5 (10.5-17) to 19.5 (15.5-21) (СЂ<0.05). SEP changed from 2 (1-2) to 3 (2-4) (СЂ<0.05). EHS improved from 1.5 (1-2) to 3 (2.5-3) (СЂ<0.05). Baseline PSV was 16.3 cm/s (12.2-22.7), at 60 days post ESWT was 24 cm/s (19.4-26.8) (СЂ<0.05) and RI changed from 0.7 (0.7-0.9) to 0.9 (0.8-1) according D-PDU (СЂ<0.05). 14 patients (70 %) noted positive dynamics by GAQ at the last exam. In group 2 IIEF-5 was 13 (11-15) at 0 days, 18 (16-20) at 60 day (СЂ<0.05). SEP improved from 2 (1.5-2) to 3 (3-4) (СЂ<0.05). EHS changed from 2 (1-2) to 3 (2-3) (СЂ<0.05). D-PDU results demonstrated increase median PSV 15.6 cm/s (12.1-22.8) to 27 cm/s (20.6-33.5) (СЂ<0.05) and median RI from 0.8 (0.7-1) to 1 (0.8-1) (СЂ=0.02). 34 men declared positive effects according to GAQ (85 %) In group 3 IIEF-5 results improved from 13 (9-15) to 18.5 (15-20.5) (СЂ<0.05). SEP improved from 2 (1-2) to 3 (3-4) (СЂ<0.05). EHS changed from 1 (1-2) to 3 (3-3) (СЂ<0.05). PSV increased from 17 cm/s (10.3-25) to 27.8 cm/s (20-36.6) (СЂ<0.05). RI improved from 0.8 (0.7-0.9) to 0.9 (0.8-1) (СЂ=0.005). 33 patients respond to an improvement of erectile functions (82.5 %) by GAQ. Conclusion. All treatment methods were well-tolerated by all patients. The study results indicate a positive trend in improving erectile function and increasing total testosterone levels in the blood. When comparing groups, combination therapy significantly improves erectile function according to SEP, EHS, and penile Doppler ultrasound assessments. ESWT can be suggested as an activator for PRP

Exploring analytical results for (2+1) dimensional breaking soliton equation and stochastic fractional Broer-Kaup system

<abstract> <p>This paper introduces a pioneering exploration of the stochastic (2+1) dimensional breaking soliton equation (SBSE) and the stochastic fractional Broer-Kaup system (SFBK), employing the first integral method to uncover explicit solutions, including trigonometric, exponential, hyperbolic, and solitary wave solutions. Despite the extensive application of the Broer-Kaup model in tsunami wave analysis and plasma physics, existing literature has largely overlooked the complexity introduced by stochastic elements and fractional dimensions. Our study fills this critical gap by extending the traditional Broer-Kaup equations through the lens of stochastic forces, thereby offering a more comprehensive framework for analyzing hydrodynamic wave models. The novelty of our approach lies in the detailed investigation of the SBSE and SFBK equations, providing new insights into the behavior of shallow water waves under the influence of randomness. This work not only advances theoretical understanding but also enhances practical analysis capabilities by illustrating the effects of noise on wave propagation. Utilizing MATLAB for visual representation, we demonstrate the efficiency and flexibility of our method in addressing these sophisticated physical processes. The analytical solutions derived here mark a significant departure from previous findings, contributing novel perspectives to the field and paving the way for future research into complex wave dynamics.</p> </abstract>

Key technologies of two-phase pulse detonation combustor

The pulse detonation combustor is a new type of power device based on periodic high-temperature and high-pressure gas generated by detonation combustion as thrust. Due to its extremely fast heat release rate, detonation combustion has the characteristics of high thermal efficiency, low fuel consumption and low pollutant emissions. In recent years, relevant institutions have conducted extensive research on pulse detonation combustors. However, most research results focus on single studies where the fuel and oxidant are in the gas phase. Based on the vision of engineering application of pulse detonation combustors, the research progress of two key pulse detonation technologies, fuel atomization blending technology and rapid short-distance low-resistance detonation technology, as well as the research status of two-phase pulse detonation combustion based on kerosene are introduced. Regarding fuel atomization and blending technology, this paper mainly introduces the fuel atomization mechanism of two-phase detonation, fuel atomization technology and oil and gas blending technology. Regarding rapid short-distance low-resistance detonation technology, it mainly introduces obstacle-assisted detonation technology, spark plug ignition technology, hot jet ignition technology, pre-detonation tube ignition technology, shock wave focusing detonation technology and plasma ignition technology.

Magnetic Hump Associated with Electron Vortex at Dipolarization Front

As the plasma boundary between two distinct plasma populations, dipolarization fronts (DFs) host abundant kinetic-scale substructures that change their normal directions and thus cause their deformation. However, studies on such deformation caused by an electron vortex have been lacking. Here, we present novel observations of a subion-scale magnetic hump (MHu) associated with an oblique electron vortex at a DF through strengthening three components of the magnetic field. A radial electric field in the MHu, showing bipolar variation, is also associated with the electron vortex as it is mainly ascribed to the electron convection term. There is apparent energy conversion ( J→·E→ ∼−0.3 nw m−3) from the particles to the electromagnetic field in the MHu’s leading part, which is accompanied by inflow and outflow of electromagnetic energy (nonzero ∇·S→ ). The other regions of the DF host opposite energy conversion ( J→·E→ > 0). Broadband parallel electrostatic waves are also observed in the MHu. Our study provides insights into the kinetic-scale processes at DFs.

Commencement and Interruption of Relativistic Electron Dropout in the Heart of the Outer Radiation Belt Induced by a Magnetic Cloud Event

AbstractWe analyze and discuss the commencement and interruption of the relativistic electron dropout in the heart of the outer radiation belt (L* = 4–5) induced by a typical magnetic cloud (MC) event. This MC event impinged the Earth’s magnetosphere on 31 October 2012 and caused a moderate geomagnetic storm with a special prolonged initial phase lasting for >13 hr. The relativistic electrons phase space density (PSD) dropout commenced at L* > 5 during the initial phase. The PSD dropout penetrated deep beyond the heart of the radiation belt (reached L* < 4) at the onset of the main phase, while it was partially enhanced with a local PSD maximum around L* = 4.5, thus causing the interruption of the PSD dropout. The dropout became pronounced at L* > ∼4.7 while the local PSD maximum was maintained throughout the main phase. During the recovery phase, the dropout totally disappeared at L* < 5.5 with relativistic electron PSD gradually recovering to pre‐event level or higher. Further investigations on solar wind parameters and plasma waves give evidence that (a) persistent high dynamic pressure and the triggered Ultra‐Low Frequency waves contribute to the dropout of electrons to interplanetary space during the initial phase and the onset of the main phase; (b) local acceleration by chorus waves during the main phase and recovery phase could explain the interruption of the dropout. Our study underlines the persistent high dynamic pressure competing with intense chorus waves in triggering the commencement and interruption of the relativistic electrons PSD dropout in the heart of the outer radiation belt.

The Dynamics of Electron Acoustic Solitary Waves in a Nonmagnetized Quantum Plasma with Two Temperature Electrons

In this article we have studied the linear and nonlinear properties of plasma waves using a one-dimensional quantum hydrodynamic (QHD) model specifically designed for quantum plasma with electron acoustic waves (EAWs). In particular, we use the standard reductive perturbation method to investigate the solitary structures resulting from nonlinearity. We use this method to derive and numerically analyze the Kortewegde Vries (KdV) equation relevant to the plasma system as well as the dispersion relation. Furthermore, in order to shed light on the dynamics of plasma waves under external influences, we investigate the temporal evolution of a forced KdV equation. PACS-52.20.j; 52.25.b; 52.30.d; 52.35.Mw; 52.65.Vv.

Topanga: A kinetic ion plasma code for large-scale ionospheric simulations on magnetohydrodynamic timescales

Topanga is a kinetic ion code developed for simulating large-scale plasma phenomena in the Earth's ionosphere on magnetohydrodynamic timescales. It is a domain-decomposed parallel code that runs on high-performance computing platforms. Features of Topanga include spherical geometry for simplified boundary conditions and computational efficiency; a hybrid plasma model with inertia-less fluid electrons, kinetic ions, and an electric field specified via an Ohm's law; a Maxwell-FDTD (finite difference time domain) plasma model which retains the displacement current in Maxwell's equations and models electron currents in the ionosphere with a tensor conductivity; sponge-layer boundary conditions for absorption of electromagnetic and plasma waves incident on the domain boundaries; and a novel mixed-implicit algorithm for evolving the EM fields inside the Maxwell-FDTD region that is stable over many orders of magnitude in the electron–ion collision frequency. We verify the numerical methods used in Topanga on a pair of test problems. The first test involves modeling a three-dimensional collisionless shock using the hybrid set of equations. The second test involves modeling a spherical TEM mode in vacuum using the Maxwell-FDTD set of equations. Finally, we demonstrate how using the combined set of hybrid and Maxwell-FDTD equations to model the Starfish Prime high-altitude nuclear test recovers a “missing” EM signal on the ground that is not present when using only the hybrid set of equations. The magnitude of this signal in the simulation containing the Maxwell-FDTD region agrees well with the E3a portion of the magnetohydrodynamic electromagnetic pulse from Starfish Prime.