Magnetic Field Spectrum Research Articles

Planck Dust Polarization Power Spectra Are Consistent with Strongly Supersonic Turbulence

The polarization of the cosmic microwave background is rich in information but obscured by foreground emission from the Milky Way’s interstellar medium (ISM). To uncover relationships between the underlying turbulent ISM and the foreground power spectra, we simulated a suite of driven, magnetized, turbulent models of the ISM, varying the fluid properties via the sonic Mach number, MS , and magnetic (Alfvén) Mach number, MA . We measure the power spectra of density (ρ), velocity (v), magnetic field (H), total projected intensity (T), parity-even polarization (E), and parity-odd polarization (B). We find that the slopes of all six quantities increase with MS . Most increase with MA , while the magnetic field spectrum steepens with MA . By comparing spectral slopes of E and B to those measured by Planck, we infer typical values of MS and MA for the ISM. As the fluid velocity increases, MS>4 , the ratio of BB power to EE power increases to approach a constant value near the Planck-observed value of ∼0.5, regardless of the magnetic field strength. We also examine correlation coefficients between projected quantities, and find that r TE ≈ 0.3, in agreement with Planck, for appropriate combinations of MS and MA . Finally, we consider parity-violating correlations r TB and r EB.

Io's Near‐Field Alfvén Wings and Local Electron Beams Inferred From Juno/Waves

AbstractJuno conducted two close Io flybys on 30 December 2023 and 03 February 2024, both at a minimum altitude of 1,500 km. Filamentary structures in the electric and magnetic field spectra indicate Juno crossed the Alfvén wing, the magnetic structure connecting Io to Jupiter's polar ionosphere. We show that the first pass took Juno diametrically through the northern Alfvén wing, while the second pass had Juno graze the southern Alfvén wing boundary, enabling extended measurements of the transition region between Io's vicinity and the Jovian magnetosphere. Of note, evidence of local electron beams is inferred from whistler‐mode emissions. We demonstrate that their energies are sub‐keV, are sourced from Io's ionosphere or local torus, and are part of a distributed current system connecting Io to Jupiter. Finally, upper hybrid resonances indicate electron densities are significantly elevated in Io's polar region (∼28,000 cm−3) compared to the local Io torus (∼2,000 cm−3).

A potential optical approach for diagnosis of the local magnetic field near the surface of the first wall/divertor tiles by Zeeman effect using polarization-resolved laser-induced breakdown spectroscopy

Magnetic field measurement is the basic diagnosis to obtain the physical engineering parameters of magnetic confinement fusion device and the macro information of plasma discharge. The real-time diagnosis of magnetic field distribution near the plasma-facing components (PFCs) surface provides the important information on the migration and transport model of key elements. In this work, a remote, in-situ approach for the magnetic field measurement near the surface of PFCs by the polarization-resolved laser-induced breakdown spectroscopy (LIBS) based on Zeeman effect is proposed and implemented. The Zeeman characteristics of the emission spectra of laser-induced W, Mo and C plasmas were verified in the laboratory by using different magnetic field configurations. According to the polarization characteristics of the Zeeman sublines of the LIBS spectrum, the intensity and direction of the external local magnetic field were successively identified by using a linear polarizer. Subsequently, a linear array fiber was utilized to determine the polarity of the external magnetic field. And finally, the magnetic field intensity near the lower edge surface of the tungsten baffle of the Experimental Advanced Superconducting Tokamak (EAST) upper divertor was measured when the field coils were demagnetized. This method can supplement the experimental data near the PFCs for the magnetic field configuration of the magnetic confinement fusion device and provide a reference for the wall element analysis model diagnosed by LIBS.

Electroluminescent vertical tunneling junctions based on WSe2 monolayer quantum emitter arrays: Exploring tunability with electric and magnetic fields

We experimentally demonstrate the creation of defects in monolayer WSe2 via nanopillar imprinting and helium ion irradiation. Based on the first method, we realize atomically thin vertical tunneling light-emitting diodes based on WSe2 monolayers hosting quantum emitters at deterministically specified locations. We characterize these emitters by investigating the evolution of their emission spectra in external electric and magnetic fields, as well as by inducing electroluminescence at low temperatures. We identify qualitatively different types of quantum emitters and classify them according to the dominant electron-hole recombination paths, determined by the mechanisms of intervalley mixing occurring in fundamental conduction and/or valence subbands.

Sample entropy-based quantitative assessment of the arc magnetic field spectrum for improved arc welding quality

Arc magnetic field analysis is a valuable approach for assessing the stability of the arc welding process, yet existing methods lack the ability to effectively quantify the disorder within the process. Through an investigation into the characteristics of the arc magnetic field signal, it was observed that the occurrence of low-frequency random fluctuations in arc magnetic field power, induced by unstable factors such as bubbles or short circuits, contributed to increased complexity and randomness in the arc magnetic field signals. To visualise the arc magnetic field signals in a time-frequency domain, a spectrogram was employed, revealing a strong correlation between the distribution of maximum power spectral density (PSD) in the spectrogram and the stability of the arc welding process. Furthermore, a novel method based on sample entropy was introduced to provide a quantitative measure of this relationship. A comprehensive quantitative assessment indicator called arc magnetic field sample entropy (AMFSE) was proposed. This indicator effectively mitigates the influence of varying parameters on the quantitative results, enabling a more accurate and consistent representation of the stability of the arc welding process. The proposed method was validated through testing, yielding an accuracy rate exceeding 90%.

A Charged Particle with Anisotropic Mass in a Perpendicular Magnetic Field–Landau Gauge

The loss of any symmetry in a system leads to quantum problems that are typically very difficult to solve. Such a situation arises for particles with anisotropic mass, like electrons in various semiconductor host materials, where it is known that they may have an anisotropic effective mass. In this work, we consider the quantum problem of a spinless charged particle with anisotropic mass in two dimensions and study the resulting energy and eigenstate spectrum in a uniform constant perpendicular magnetic field when a Landau gauge is adopted. The exact analytic solution to the problem is obtained for arbitrary values of the anisotropic mass using a mathematical technique that relies on the scaling of the original coordinates. The characteristic features of the energy spectrum and corresponding eigenstate wave functions are analyzed. The results of this study are expected to be of interest to quantum Hall effect theory.

Jovian Magnetosheath Turbulence Driven by Whistler

Jupiter’s magnetosheath is a natural yet complex laboratory for analyzing compressible plasma turbulence. Recent observations by the Juno mission provide a promising opportunity for the first time to reckon the energy cascade rate in the magnetohydrodynamic scales in the vicinity of Jupiter’s space. In the present work, a two-dimensional model is constructed for a whistler wave that is nonlinearly coupled with a wave magnetic field via ion density perturbation. The dynamics of whistler wave propagating in the direction of the magnetic field are derived within the limit of the two-fluid modeling approach. The magnetic field localization along with magnetic field spectra and spectral slope variations are estimated to realize the turbulence generation and energy cascade from large to small scales in the Jovian magnetosheath region. The simulated magnetic field spectrum in the wave number (in the unit of ion inertial length ρ i ) consists of turbulence in the inertial range with a spectral slope of −1.4 and a spectral knee at k ρ i = 1. Subsequently, the spectral slope increases to −2.6 and the spectrum becomes steeper. The simulated magnetic field spectrum in the wave number is further translated into the frequency domain using the whistler wave dispersion relation and by considering the Taylor frozen-in condition. The analytically estimated magnetic field spectrum slopes, i.e., −1.8 and −4.2 at low and high frequencies are further compared with recent Juno mission observations. The comparison further affirms the existence of Kolmogorov scaling, a spectral knee, and steepening in the spectrum at high frequencies. Furthermore, it is found that the two-fluid model can reasonably simulate the turbulence effects in Jovian magnetosheath in terms of magnetic field spectral distribution in wave number and frequency domains.

Influence of pressure and temperature on the magneto-optical properties and Aharonov-Bohm oscillations of a quantum ring

We theoretically investigated the influence of pressure and temperature on the electronic and optical properties of a GaAs /Al0.3Ga0.7As quantum ring, described by a combination of a parabolic potential and an inverse square one, in the presence of the magnetic field. The results reveal a variation with pressure and temperature of the period of Aharonov-Bohm oscillations appearing in the electronic spectra in magnetic field. This period varies nonlinearly with pressure and temperature. In the absorption spectra and refractive index variation at 4 K, we found that with the increment of the magnetic field or of the pressure more transitions are allowed. When no external pressure is applied, the absorption maxima shift to lower energies at increasing magnetic field, but with increasing pressure, the absorption maxima red-shift at intermediate magnetic fields and blue-shift at high fields.

Диагностика неисправностей синхронных генераторов путем компьютерного моделирования внешнего магнитного поля

Currently, the development of non-invasive diagnostic methods for electric machines and especially generators, as the main producers of electric energy, using magnetic field fixation sensors is an urgent scientific and technical task. To solve this problem, research has been conducted to develop a method for troubleshooting a synchronous generator by analyzing an external magnetic field. The article discusses the main issues of computer modeling of an external magnetic field in the FEMM 4.2 system for troubleshooting. Mathematical expressions are given for creating a computer model of a synchronous generator in two-dimensional space, on the basis of which a numerical solution of the external magnetic field is formed using the finite element method. The modeling takes into account the design features of the synchronous generator. The main stages of work in the FEMM 4.2 system are defined. The geometric model of the synchronous generator is imported from the computer-aided design system. The physical properties of all elements of the model are determined by the structural materials of the synchronous generator and the external space. The control program, created on the basis of the algorithm presented in the article, allows you to simulate the rotation of the inductor of a synchronous generator, automate the calculations of the electromagnetic field and display the results. An example of using a computer model of a synchronous generator for troubleshooting by examining an external magnetic field is given. Based on the results of a numerical solution of the external magnetic field, a harmonic analysis of the magnetic induction of a working synchronous generator was carried out. The article shows that a diagnostic sign of static eccentricity of a synchronous generator inductor is the appearance of even harmonics in the magnetic induction spectrum of an external magnetic field Based on the results obtained, the dependence of the growth of even harmonics on the magnitude of the displacement of the inductor of the synchronous generator is determined.

Magnetic power spectrum variability with large-scale total magnetic field fluctuations

The Parker Solar Probe (PSP) is operational since 2018 and has provided invaluable new data that measure the solar vicinity in situ at smaller heliocentric distances than ever before. These data can be used to shed new light on the turbulent dynamics in the solar atmosphere and solar wind, which in turn are thought to be important to explain long-standing problems of the heating and acceleration in these regions. In recent years, it was realized that background inhomogeneities in magnetohydrodynamics could influence the development of turbulence and might enable other cascade channels, such as the self-cascade of waves, in addition to the well-known Alfvén collisional cascade. This phenomenon has been called uniturbulence. However, the precise influence of the background inhomogeneity on turbulent spectra has not been not studied so far. In this work, we study the influence of background roughness on the turbulent magnetic field spectrum in PSP data, including data from encounter 1 up to and including encounter 14. The magnetic spectral index $ receives our highest attention. Motivated by the presumably different turbulent dynamics in the presence of large-scale inhomogeneities, we searched for correlations between the magnetic power spectra and a measure for the degree of inhomogeneity. The latter was probed by taking the standard deviation (STD) of the total magnetic field magnitude after applying an appropriate averaging. The data of each PSP encounter were split into many short time windows, of which we subsequently calculated both $ and background STD. We find a significant impact of the background STD on $ As the variations in the background become stronger, $ becomes more negative, indicating a steepening of the magnetic power spectrum. We show that this effect is consistent in all investigated PSP encounters, and it is unaffected by heliocentric distance up to $50 R_ By making use of artificial magnetic field data in the form of synthetic colored noise, we show that this effect is not simply due to the fluctuations imposed on the total magnetic field, but must have another as yet unidentified cause. There is a strong indication that the background inhomogeneity affects the turbulent dynamics, possibly through uniturbulence. This leads to a different power spectrum in the presence of large-scale total magnetic field variations. The fact that it is present in all investigated encounters and at all radial distances up to $50 R_ suggests that it represents a general and ubiquitous feature of solar wind dynamics. The analysis with the synthetic colored noise indicates that the observed steepening effect is not to be attributed simply to the small-scale fluctuations superposed on the total magnetic field. This conclusion is confirmed by the fact that no similar consistent steepening trend is observed for the magnetic compressibility $C_b$ instead of background STD. The steepening trend is instead a real physical effect induced by the large-scale variations in the background magnetic field.

Proton- and Alpha-driven Instabilities in an Ion Cyclotron Wave Event

Ion-scale wave events or wave storms in the solar wind are characterized by enhancements in magnetic field fluctuations as well as coherent magnetic field polarization signatures at or around the local ion cyclotron frequencies. In this paper, we study in detail one such wave event from Parker Solar Probe's (PSP) fourth encounter, consisting of an initial period of left-handed (LH) polarization abruptly transitioning to a strong period of right-handed (RH) polarization, accompanied by a clear core beam structure in both the alpha and proton velocity distribution functions. A linear stability analysis shows that the LH-polarized waves are anti-sunward propagating Alfvén/ion cyclotron waves primarily driven by a proton cyclotron instability in the proton core population, and the RH polarized waves are anti-sunward propagating fast magnetosonic/whistler waves driven by a firehose-like instability in the secondary alpha beam population. The abrupt transition from LH to RH is caused by a drop in the proton core temperature anisotropy. We find very good agreement between the frequencies and polarizations of the unstable wave modes as predicted by linear theory and those observed in the magnetic field spectra. Given the ubiquity of ion-scale wave signatures observed by PSP, this work gives insight into which exact instabilities may be active and mediating energy transfer in wave–particle interactions in the inner heliosphere, as well as highlighting the role a secondary alpha population may play as a rarely considered source of free energy available for producing wave activity.

Various facets of intermolecular transfer of phase coherence by nuclear dipolar fields.

It has long been recognized that dipolar fields can mediate intermolecular transfer of phase coherence from abundant solvent to sparse solute spins. Generally, the dipolar field has been considered while acting during prolonged free-precession delays. Recently, we have shown that transfer can also occur during suitable uninterrupted radio frequency pulse trains that are used for total correlation spectroscopy. Here, we will expand upon the latter work. First, analytical expressions for the evolution of the solvent magnetization under continuous irradiation and the influence of the dipolar field are derived. These expressions facilitate the simulations of the transfer process. Then, a pulse sequence for the retrieval of high-resolution spectra in inhomogeneous magnetic fields is described, along with another sequence to detect a transfer from an intermolecular double-quantum coherence. Finally, various schemes are discussed where the magnetization is modulated by a combination of multiple selective radio frequency pulses and pulsed field gradients in different directions. In these schemes, the magnetization is manipulated in such a way that the dipolar field, which originates from a single-spin species, can be decomposed into two components. Each component originates from a part of the magnetization that is modulated in a different direction. Both can independently, but simultaneously, mediate an intermolecular transfer of phase coherence.

Magnetic-field-induced splitting of Rydberg Electromagnetically Induced Transparency and Autler-Townes spectra in 87Rb vapor cell.

We theoretically and experimentally investigate the Rydberg electromagnetically induced transparency (EIT) and Autler-Townes (AT) splitting of 87Rb vapor under the combined influence of a magnetic field and a microwave field. In the presence of static magnetic field, the effect of the microwave field leads to the dressing and splitting of each mF state, resulting in multiple spectral peaks in the EIT-AT spectrum. A simplified analytical formula was developed to explain the EIT-AT spectrum in a static magnetic field, and the theoretical calculations agree qualitatively with experimental results. The Rydberg atom microwave electric field sensor performance was enhanced by making use of the splitting interval between the two maximum absolute mF states separated by the static magnetic field, which was attributed to the stronger Clebsch-Gordon coefficients between the extreme mF states and the frequency detuning of the microwave electric field under the static magnetic field. The traceable measurement limit of weak electric field by EIT-AT splitting method was extended by an order of magnitude, which is promising for precise microwave electric field measurement.

Universal scaling of tunable Yu-Shiba-Rusinov states across the quantum phase transition

Quantum magnetic impurities give rise to a wealth of phenomena attracting tremendous research interest in recent years. On a normal metal, magnetic impurities generate the correlation-driven Kondo effect. On a superconductor, bound states emerge inside the superconducting gap called the Yu-Shiba-Rusinov (YSR) states. Theoretically, quantum impurity problems have been successfully tackled by numerical renormalization group (NRG) theory, where the Kondo and YSR physics are shown to be unified and the normalized YSR energy scales universally with the Kondo temperature divided by the superconducting gap. However, experimentally the Kondo temperature is usually extracted from phenomenological approaches, which gives rise to significant uncertainties and cannot account for magnetic fields properly. Using scanning tunneling microscopy at 10 mK, we apply a magnetic field to several YSR impurities on a vanadium tip to reveal the Kondo effect and employ the microscopic single impurity Anderson model with NRG to fit the Kondo spectra in magnetic fields accurately and extract the corresponding Kondo temperature unambiguously. Some YSR states move across the quantum phase transition (QPT) due to the changes in atomic forces during tip approach, yielding a continuous universal scaling with quantitative precision for quantum spin-frac{1}{2} impurities.

Efficient kinetic Lattice Boltzmann simulation of three-dimensional Hall-MHD turbulence

Simulating plasmas in the Hall-magnetohydrodynamics (Hall-MHD) regime represents a valuable approach for the investigation of complex nonlinear dynamics developing in astrophysical frameworks and fusion machines. The Hall electric field is computationally very challenging as it involves the integration of an additional term, proportional to $\boldsymbol {\nabla } \times ((\boldsymbol {\nabla }\times \boldsymbol {B})\times \boldsymbol {B})$ , in Faraday's induction law. The latter feeds back on the magnetic field $B$ at small scales (between the ion and electron inertial scales), requiring very high resolutions in both space and time to properly describe its dynamics. The computational advantage provided by the kinetic lattice Boltzmann (LB) approach is exploited here to develop a new code, the fast lattice-Boltzmann algorithm for MHD experiments (flame). The flame code integrates the plasma dynamics in lattice units coupling two kinetic schemes, one for the fluid protons (including the Lorentz force), the other to solve the induction equation describing the evolution of the magnetic field. Here, the newly developed algorithm is tested against an analytical wave-solution of the dissipative Hall-MHD equations, pointing out its stability and second-order convergence, over a wide range of the control parameters. Spectral properties of the simulated plasma are finally compared with those obtained from numerical solutions from the well-established pseudo-spectral code ghost. Furthermore, the LB simulations we present, varying the Hall parameter, highlight the transition from the MHD to the Hall-MHD regime, in excellent agreement with the magnetic field spectra measured in the solar wind.

Revisiting kinematic fast dynamo in three-dimensional magnetohydrodynamicplasmas: dynamo transition from non-helical to helical flows

Dynamos wherein magnetic field is produced from velocity fluctuations are fundamental to our understanding of several astrophysical and/or laboratory phenomena. Though fluid helicity is known to play a key role in the onset of dynamo action, its effect is yet to be fully understood. In this work, a fluid flow proposed recently (Yoshida et al 2017, Phys. Rev. Lett. 119, 244501) is invoked such that one may inject zero or finite fluid helicity using a control parameter, at the beginning of the simulation. Using a simple kinematic dynamo model, for the considered flow, we demonstrate unambiguously a strong dependency of short scale dynamo on fluid helicity. In contrast to conventional understanding, it is shown that fluid helicity does strongly influence the physics of short scale dynamo for the flow profiles considered. To corroborate our findings, late time magnetic field spectra for various values of injected fluid helicity is presented along with ‘geometric” signatures of the 3D magnetic field surfaces, which shows a transition from ‘twisted ribbon’ or ‘twisted’ sheet to ‘cigar’ like configurations. This work brings out, for the first time, the role of fluid helicity in the transition from ‘non-dynamo’ to ‘dynamo’ regime systematically. It is also shown that one of the most studied ABC dynamo model is not the ”fastest’ dynamo model for problems at lower magnetic Reynolds number.

Cavity Mode Wave Frequency Variation Associated With Inward Motion of the Magnetopause During Interplanetary Shock Compression

AbstractA cavity mode wave, referring to a trapped or radially standing fast mode wave between different magnetospheric boundaries, has been developed in theory and reported in observation studies. In this study, we present an interplanetary shock (IPS)‐induced cavity mode wave event observed outside the plasmasphere on 31 August 2017 with multispacecraft measurements. The phase delay of 90° between the azimuthal electric field and compressional magnetic field indicates that the fast‐mode wave triggered by the IPS is a standing wave, presumably radially trapped in the cavity between the magnetopause and plasmapause. Taking advantage of the location of Van Allen Probe B spacecraft right outside the plasmapause and the Arctic and Antarctic Research Institute ground‐based high‐latitude array mapped in the noon sector, it is suggested that the observed compressional wave associates to cavity mode with its inner boundary at the plasmapause and its outer boundary at the magnetopause. The peak frequency of the wavelet spectrum of the compressional magnetic field increases from 10.5 to 12.5 mHz, which is consistent with the theoretically calculated cavity eigenfrequencies before and after the IPS. We also provide the first evidence that the peak frequency of the cavity mode increases due to the inward motion of the magnetopause during IPS compression.

Modeling the Time‐Dependent Magnetic Fields That BepiColombo Will Use to Probe Down Into Mercury's Mantle

AbstractExternal solar wind variability causes motion of the magnetopause and changes of this boundary's current structure, and the resulting inductive processes, may be exploited to determine the interior structure of magnetized planets. In preparation for the arrival of the BepiColombo spacecraft at Mercury, we here assess solar wind ram pressure forcing in this planet's environment, through analysis of data acquired by the Helios spacecraft, and the impact on the magnetopause's inducing field. These measurements suggest that BepiColombo will see highly unpredictable solar wind conditions and that the inducing field generated in response to variable solar wind ram pressure is non‐uniform across the planet's surface. The inducing magnetic field spectrum, with frequencies in the range of , suggests that the transfer functions derived from the two BepiColombo spacecraft could allow us to obtain a profile of conductivity through Mercury's crust and mantle.

Pre-seismic multi-parameters variations before Yangbi and Madoi earthquakes on May 21, 2021

On May 21, a Ms6.4 earthquake occurred in Yangbi, Yunnan Province. Less than 5 ​h later, on May 21, follows a Ms7.4 earthquake in Madoi, Qinghai Province. In this study, multiple parameters are studied from CSES-01 satellite and GNSS. The parameters include the electron density from LAP, energetic particle flux from HEPP, electric field spectrum from EFD, induced magnetic field spectrum from SCM, and global TEC from ground-based GNSS receivers. In the time scale, all parameters changed on May 15, 17 and 18. The relative amplitude of Ne is more than 200%. In space scale, the clear enhancement focus on the southeast of the epicenter of Madoi, Qinghai, and the shape of the focus region is like a clockwise-30°-rotated rectangle, which is about 45° in length and 20° in width. Moreover, there appeared enhancement in the conjugated region. According to the day-to-day analysis of the low-frequency (75–90 Hz) spectrum of EFD and SCM payloads, the relationship of the increment on May 18 could be confirmed with the successive two earthquakes. The energetic particle fluxes enhanced on May 20. All those changes are located in the east of the following epicenter and appeared just several days before, which could be well explained by the Lithosphere-Atmosphere-Ionosphere theory.

Spectral properties and energy transfer at kinetic scales in collisionless plasma turbulence

Context. Recent satellite observations in the solar wind and in the Earth’s magnetosheath have shown that the turbulent magnetic field spectrum, which is know to steepen around ion scales, has another break at electron scales where it becomes even steeper. The origin of this second spectral break is not yet fully understood, and the shape of the magnetic field spectrum below electron scales is still under debate. Aims. By means of a fully kinetic simulation of freely decaying plasma turbulence, we study the spectral properties and the energy exchanges characterizing the turbulent cascade in the kinetic range. Methods. We started by analyzing the magnetic field, electron velocity, and ion velocity spectra at fully developed turbulence. We then investigated the dynamics responsible for the development of the kinetic scale cascade by analyzing the ion and electron filtered energy conversion channels, represented by the electromagnetic work J ⋅ E, pressure–strain interaction −P : ∇ u, and the cross-scale fluxes of electromagnetic (e.m.) energy and fluid flow energy, accounting for the nonlinear scale-to-scale transfer of energy from large to small scales. Results. We find that the magnetic field spectrum follows the k−α exp(−λ k) law at kinetic scales with α ≃ 2.73 and λ ≃ ρe (where ρe is the electron gyroradius). The same law with α ≃ 0.94 and λ ≃ 0.87ρe is observed in the electron velocity spectrum, but not in the ion velocity spectrum that drops as a steep power law ∼k−3.25 before reaching electron scales. By analyzing the filtered energy conversion channels, we find that electrons play a major role with respect to the ions in driving the magnetic field dynamics at kinetic scales. Our analysis reveals the presence of an indirect electron-driven mechanism that channels the e.m. energy from large to sub-ion scales more efficiently than the direct nonlinear scale-to-scale transfer of e.m. energy. This mechanism consists of three steps. In the first step the e.m. energy is converted into electron fluid flow energy at large scales; in the second step the electron fluid flow energy is nonlinearly transferred toward sub-ion scales; in the final step the electron fluid flow energy is converted back into e.m. energy at sub-ion scales. This electron-driven transfer drives the magnetic field cascade up to fully developed turbulence, after which dissipation becomes dominant and the electrons start to subtract energy from the magnetic field and dissipate it via the pressure–strain interaction at sub-ion scales.