Electric currents induced in conductive planetary interiors by time‐varying magnetospheric and ionospheric current systems have a significant effect on electromagnetic (EM) field observations. Complete characterization of EM induction effects is difficult owing to non‐linear interactions between the three‐dimensional (3‐D) electrical structure of a planet and spatial complexity of inducing current

We study the interaction of three solar wind structures, two stream interaction regions and one interplanetary coronal mass ejection, with Mars’ plasma environment during 20‐27 November 2007. This period corresponds to the solar minimum between the solar cycles 23 and 24 which was characterized by very low values of the solar wind density and dynamic pressure and low IMF magnitude. During that time

We present an investigation of polar cap plasma structure lifetimes. We analyze both simulated data from ionospheric models (International Reference Ionosphere model and Mass Spectrometer Incoherent Scatter model) and in‐situ data from the Swarm satellite mission (the 16 Hz Advanced Plasma Density data set). We find that the theoretical prediction that E‐region conductance is a predictor of F‐region

We investigate the ionospheric responses to the 2014‐2015 SSW (Sudden Stratospheric Warming) event in winter and summer hemisphere by using ionosondes distributed in Equatorial Ionization Anomaly (EIA) crests. Daily mean value of foF2 at each station shows obvious semimonthly lunar tide (∼14.5‐day period) modulation from lower to higher latitude in both hemispheres during SSW period. Besides, lunar

In this study, the excitation of narrowband fast magnetosonic (MS) waves near the lower hybrid resonance frequency (fLHR) has been investigated with observations from Van Allen Probes mission and linear growth theory. A typical wave event is first examined to show that these waves can be excited through linear instabilities driven by partial shell distributions of protons. Then it is found that these

The present investigation evaluates the assimilation of synthetic data which has properties similar to actual Global‐scale Observations of the Limb and Disk (GOLD) level‐2 (L2) temperatures and other conventional lower atmospheric observations. The lower atmospheric and GOLD L2 temperature (Tdisk) are assimilated in the Whole Atmosphere Community Climate Model with thermosphere‐ionosphere eXtension

Aurora provides an essential diagnostic to spatial and temporal variations of terrestrial space environment and is also an important proxy of solar and geomagnetic activities. Contemporary auroral observations have just continued for more than half a century. Visual auroral phenomena recorded in historical books provide key clues to understand the solar and geomagnetic activities in the long history

This paper presents and discusses electron density depletion regions observed with the incoherent scatter EISCAT Svalbard Radar (ESR) located at 75.43°N geomagnetic latitude. The data include several decades of measurements, which make them suitable for studying statistical features and characteristics of the ionospheric parameters. Here we focus on the electron density depletions and their dependence

During magnetospheric substorms, high‐latitude ionospheric plasma convection is known to change dramatically. How upper thermospheric winds change, however, has not been well understood, and conflicting conclusions have been reported. Here, we study the effect of substorms on high‐latitude upper thermospheric winds by taking advantage of a chain of scanning Doppler imagers (SDIs), THEMIS all‐sky imagers

With the interplanetary magnetic field (IMF) that turns from northward to southward, the global simulation successively reproduces the growth phase, the onset, and the expansion phase of the substorm. The calculated ionospheric convection for the growth phase reproduces the development of the Harang reversal (HR), the upward field‐aligned current (FAC), and the upcoming onset point as observed. Magnetic

Acceleration of single‐ and multi‐charged oxygen ions in the perturbed Earth's magnetotail is investigated as the possible source of energetic heavy ions in the ring current. The numerical model is developed that allows evaluating the acceleration of oxygen ions O+‐O+8 in two possible scenarios of characteristic perturbations: (A) passage of multiple dipolarization fronts in the magnetotail; (B) passage

We analyzed the magnetospheric global response to dynamic pressure pulses (DPPs) using the Heliophysics System Observatory (HSO) and ground magnetometers. During northward Interplanetary Magnetic Field (IMF) Bz conditions, the magnetosphere acts as a closed “cavity” and reacts to solar wind DPPs more simply than during southward IMF. In this study we use solar wind data collected by ACE and WIND together

We report new findings of total electron content (TEC) perturbations in the southern hemisphere at conjugate locations to the northern eclipse on 21 August 2017. We identified a persistent conjugate TEC depletion by 10‐15% during the eclipse time, elongating along magnetic latitudes with at least ∼5° latitudinal width. As the Moon's shadow swept southward, this conjugate depletion moved northward and

The TianQin space Gravitational Waves (GW) observatory will contain 3 geocentric and circularly orbiting spacecraft with an orbital radius of 105 km, to detect the GW in the milli‐hertz frequency band. Each spacecraft pair will establish a 1.7×105 km‐long laser interferometer immersed in the solar wind and the magnetospheric plasmas to measure the phase deviations induced by the GW. GW detection requires

In this study, the mass densities from Challenging Minisatellite Payload (CHAMP) and Gravity Recovery And Climate Experiment (GRACE) satellites and the simulation results from the Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) have been used to systematically explore the peak response time (or time delay hereafter) of thermospheric mass density to the 27‐day solar extreme

With a 1‐D PIC simulation model, we have investigated the gap formation around 0.5Ωe of the quasi‐parallel (with the wave normal angle of 20°) whistler‐mode waves excited by an electron temperature anisotropy. When the frequencies of excited waves in the linear stage cross 0.5Ωe, or when they are slightly larger than 0.5Ωe but then drift to lower values, the Landau resonance can make the electron distribution

We report the properties of the ionospheric exit point and characteristics of several types of very low frequency waves, including chorus and quasi‐periodic emissions, based on a comprehensive data set of simultaneous observations between ground and space. Whistler‐mode waves were observed at Kannuslehto (L=5.5, KAN), Finland, and in the inner magnetosphere by the Japanese Arase satellite. During the

The nature and origins of longitudinal density structures in Mars′ thermosphere between 100 and 120 km altitude, and − 30° and − 75° latitude around winter solstice (Ls = 70°‐122°), as measured by the accelerometer on the ExoMars Trace Gas Orbiter (TGO) Mission, are investigated. The methodology consists of deducing the responsible waves by comparing the observed longitude vs. local time phase progressions

Whistlers that originate from lightning strokes are among the prevalent wave phenomena in the magnetosphere, which makes their interactions with magnetospheric plasma particles of particular importance. We develop a theory that takes into account the main features of this interaction, namely, the space‐time boundedness of wave packets representing magnetospherically reflected whistlers, and the variation

We present the discovery of seven new flux transfer events (FTEs) at Saturn's dayside magnetopause by the Cassini spacecraft and analyze the observations of all eight known FTEs. We investigate how FTEs may differ at Saturn where the magnetopause conditions are likely to diamagnetically suppress magnetic reconnection from occurring. The measured ion‐scale FTEs have diameters close to or above the ion

Flux ropes are ubiquitous at Earth's magnetopause and play important roles in energy transport between the solar wind and Earth's magnetosphere. In this paper, structure and coalescence of the magnetopause flux ropes formed by multiple X line reconnection in cases with different southward interplanetary magnetic field (IMF) clock angles are investigated by using three‐dimensional global hybrid simulations

In this study, electron temperature (Te) observations from the Defense Meteorological Satellite Program (DMSP) F17 and F18 spacecraft during 2010 to 2017 are analyzed to explore the longitudinal differences of Te in the topside ionosphere on both sides of zero geomagnetic declination lines in the northern mid‐latitude under geomagnetically weak activities (Kp3). Te in the North American sector (45º‐135ºW)

Using measurements from Cluster‐II space mission, we compared the characteristics of the fluctuations of the magnetic field magnitude and the Bz component in the current disruption (CD) regions. We used fast Fourier transform, statistical, and wavelet analysis, and wave surveyor technique on the multispacecraft measurements. Among the obtained results one can note the presence of spectral breaks in

Decomposing the electric field (E) into the contributions from generalized Ohm's law provides key insight into both nonlinear and dissipative dynamics across the full range of scales within a plasma. Using high‐resolution, multispacecraft measurements of three intervals in Earth's magnetosheath from the Magnetospheric Multiscale mission, the influence of the magnetohydrodynamic, Hall, electron pressure

The fracture theory for auroral arcs, developed by the author since 1980, compares the decoupling of the magnetic field from the ionosphere by the auroral acceleration region (AAR) with the breaking of a solid rod. In the latter elastic energy stored by the bending is converted into kinetic energy of the stress release motion. Similarly, magnetic energy stored in sheared magnetic fields is temporarily

Radiation belt electrons have a complicated relationship with geomagnetic activity. We select electron measurements from 7 years of DEMETER and 6 years of Van Allen Probes data during geomagnetic storms to conduct statistical analysis focusing on the correlation between electron flux and Dst index. We report, for the first time, an upper limit of electron fluxes observed by both satellites throughout

Santa Maria Digisonde data are used for the first time to investigate the F region behavior during a geomagnetic storm. The August 25, 2018 storm is considered complex due to the incidence of two Interplanetary Coronal Mass Ejections and a High‐Speed Solar Wind Stream (HSS). The F 2 layer critical frequency (f o F 2) and its peak height (h m F 2) collected over Santa Maria, near the center of the South

Phase space holes, double layers and other solitary electric field structures, referred to as time domain structures (TDSs), often occur around dipolarization fronts in the Earth's inner magnetosphere. They are considered to be important because of their role in the dissipation of the injection energy and their potential for significant particle scattering and acceleration. Kinetic Alfvén waves are

Typical planetary and planetary satellite exospheres are in non‐equilibrium conditions, which means that a distribution function that describes these environments is far from Maxwellian. It is even more true when considering transportation of energetic ions in planetary magnetospheres, making it necessary to solve the Boltzmann equation in order to capture kinetic effects when modeling evolution of

The two Van Allen Probes simultaneously recorded a coherently modulated quasiperiodic (QP) emission that persisted for 3 hours. The magnetic field pulsation at the locations of the two satellites showed a substantial difference, and their frequencies were close to but did not exactly match the repetition frequency of QP emissions for most of the time, suggesting that those coherent QP emissions probably

The ring current experiences dramatic enhancements during geomagnetic storms, however understanding the global distribution of ring current energy content is restricted by spacecraft coverage. Many studies use ring current indices as a proxy for energy content, but these indices average over spatial variations and include additional contributions. We have conducted an analysis of Van Allen Probes’

We report observations of the whistler mode waves in the magnetic reconnection region at the dayside magnetopause using the Magnetospheric Multiscale (MMS) mission on 11 January 2016. In this event, whistlers mostly occur on the magnetospheric side of the reconnection central plane and are closely related to counter‐streaming electron beams in the medium energy range (200‐300 eV). These counter‐streaming

Due to the sparsity of space probes, it is still not clear on how the magnetic structure of the magnetotail looks like and how it evolves when the Interplanetary Magnetic Field (IMF) directs northward. This simulation study uses two different global magnetosphere MHD models to simulate two northward IMF events and study the evolution of the magnetotail. Both models show that the magnetotail may form

Polar cap patches are islands of enhanced electron density in the polar cap F region ionosphere, which sometimes affect the propagation of trans‐ionospheric radio waves. Considering the intake of daytime sunlit plasma by the high‐latitude convection as the primary cause of patches, the spatial overlap between the convection and the daytime sunlit plasma should be one of the critical factors controlling

An extended interval of perturbed magnetospheric conditions in November 2016 supported increased convection and sunward transport of plasmaspheric material. During this period of time the Magnetospheric Multiscale satellites, with their apogees along Earth's dusk‐side outer magnetosphere, encountered several cold plasma density structures at the same time as plasma bulk flows capable of accelerating

The collision between atomic oxygen and its first positive ion plays a major role in Earth's F region ionosphere. An accurate corresponding collision frequency model is necessary to quantitatively understand the ionosphere. However, the widely used classic Banks theoretical model typically provides a collision frequency that is 30% lower than the expectation from ionospheric observations. Accordingly

First results are presented of the modeling of magnetospheric storm events, based on: (i) a new method to represent the magnetic field by means of the so‐called cylindrical basis functions (CBF), (ii) the data mining approach by Sitnov et al. (2008), and (iii) upgraded and extended pool of multi‐mission data taken in 1995–2019. The study is focused on the low‐latitude magnetospheric domain in the distance

Accurate estimates of extreme ultraviolet (EUV) irradiance are needed in order to understand the dynamical, chemical, and plasma processes occurring in planetary upper and tenuous atmospheres. Most studies rely on irradiance measurements made at Earth, which are extrapolated to the location of interest. The Mars Atmosphere and Volatile Evolution (MAVEN) orbiter includes the Extreme Ultraviolet Monitor

The magnetosphere‐ionosphere (MI) coupling is crucial in modeling the thermosphere‐ionosphere (TI) response to geomagnetic activity. In general circulation models (GCMs) the MI coupling is typically realized by specifying the ion convection and auroral particle precipitation patterns from for example, empirical or assimilative models. Assimilative models, such as the Assimilative Mapping of Ionospheric

Based on magnetic field fluctuations, Saturn's magnetosphere can be divided into quiet (little or not much fluctuation) and disturbed periods (large fluctuation of the magnetic field). Kaminker et al. (2017, https://doi.org/10.1002/2016JA023834) showed that the average heating rate density of entire magnetosphere of Saturn is ∼10−17 W m−3 based on magnetic field fluctuations. Here, we categorize the

Ionospheric escape from Mars is an important process for the erosion of the Martian atmosphere. The heavy ion outflow is dominated by and O+, however, the Martian ionosphere consists of many more ion species. In the dayside ionosphere below roughly 220 km altitude, is the second most dominant ion, and higher up and in the nightside ionosphere other ions species with a mass near but below that of (28–30

We present theoretical and computational analyses of energy conversions in a magnetized collisionless plasma. We first revisit the theoretical approach to energy conversion analysis and discuss the expected correlations between the different conversion terms. We then present results from a Hybrid‐Vlasov simulation of a turbulent plasma, focusing on the immediate vicinity of a reconnection site. Energy

During geomagnetic storms, the ring current ions sometimes exhibit rapid loss as suggested by the fast recovery of the Dst index on a time scale of a few hours. The effects of magnetic field line curvature (FLC) scattering on the loss of ring current ions, which have not been well quantified, are studied here by test particle simulations under the T89c magnetic field model. Our simulation results show

The polar cap magnetic activity PC index is regarded as indicator of the solar wind energy that enters into the magnetosphere during the solar wind‐magnetosphere coupling (Resolutions of XXII IAGA Assembly, 2013). This study presents the results of statistical analysis of relationships between the yearly values of PC index and such indicators as the magnetic activity indices (AE and Dst), the solar

No abstract is available for this article.

We investigate the rare events of sudden appearances of relativistic electrons (>700 keV), which are normally confined to the Van Allen belts, in the slot region. The frequency of occurrence of these events is on average 1–2 per year. To cope with the scarcity of events, in this study, we examine 21 years of trapped relativistic electron fluxes available from the POES and MetOp Space Environment Monitor

The westward quasi‐6‐day wave (Q6DW) with zonal wavenumber 1 is a prominent and recurrent phenomenon in the mesosphere and lower thermosphere (MLT) and has a significant impact on day‐to‐day ionospheric variability. Geopotential height measurements from Aura Microwave Limb Sounder and Specified Dynamics Whole Atmosphere Community Climate Model eXtended Version simulations during 2005–2019 are utilized

We report on observations of electromagnetic ion cyclotron (EMIC) waves and their interactions with injected ring current particles and high energy radiation belt electrons. The magnetic field experiment aboard the twin Van Allen Probes spacecraft measured EMIC waves near L = 5.5 − 6. Particle data from the spacecraft show that the waves were associated with particle injections. The wave activity was

We present a new high resolution empirical model for the ionospheric total electron content (TEC). TEC data are obtained from the global navigation satellite system (GNSS) receivers with a 1o x 1o spatial resolution and 5 minute temporal resolution. The linear regression model is developed at 45o N, 0o E for the years 2000 ‐ 2019 with 30 minute temporal resolution, unprecedented for typical empirical

Fast magnetosonic (MS) waves are excited by the ring distribution of energetic protons preferably when the ring velocity (VR) is within a factor of 2 above or below the local Alfvén speed (VA). Here we examine the global distributions of MS waves and proton rings with 0.5VA ≤ VR ≤ 2VA based on 64 months (from October 25, 2012 to February 28, 2018) of Van Allen Probes observations. The statistical results

Quantitatively estimating magnetotail flapping motion is critical for understanding and characterizing its dynamical behaviors. Such estimation can be achieved in principle by the multipoint analysis of spacecraft tetrahedron, e.g. Cluster or MMS mission, but, owing to the inability of single‐point measurement to separate the spatial‐temporal variation of magnetic field, would be inadequate for a single

Over the last few decades, the role of ionospheric outflow for the loss of atmospheric constituents, as a plasma supplier to the magnetosphere and hence for the evolution of the Earth's atmosphere has been recognized. A substantial amount of the outflow is thought to be caused by the presence of an ambipolar electric field aligned with the open magnetic field lines of the polar region. To better understand

Kappa distributions possess an enhanced high‐energy tail characterized by a spectral index κ. Here we consider how kappa distributions influence the whistler mode instability. In a relativistic regime, we analyze the effects of the bi‐kappa and kappa loss‐cone distributions on the linear and nonlinear growth of whistler mode waves. We find that for κ = 2, the linear growth rate corresponding to the

We utilize 17 years of combined Van Allen Probes and Arase data to statistically analyze the response of the inner magnetosphere to the orientation of the interplanetary magnetic field (IMF) By component. Past studies have demonstrated that the IMF By component introduces a similarly oriented By component into the magnetosphere. However, these studies have tended to focus on field lines in the magnetotail

A theorem is proved that the minimum Nyquist compatible cadence Δτ for subsequent model free determinations of current density J by magnetospheric multiscale (MMS) instrumentation is the cadence of the ion plasma subsystem DIS of the fast plasma investigation (FPI). A sample of published discoveries and signatures of magnetic dissipation associated with collisionless magnetic reconnection at the noon

Ring current decay during storm recovery phase may be affected by different loss processes. In this study, we have investigated the lifetimes of ring current ions (H+ and O+) of energies from 1 keV to several hundred keV at L shell from 3 to 6 during the storm recovery phase through a statistical survey. The observational data of 48 geomagnetic storms from March 2013 to May 2019 are collected based

Internal gravity waves (IGWs) play an important role in the planetary atmospheres, which transfer energy and momentum from the lower layers to the upper atmosphere. However, the IGW perturbations and behaviors are not clear in the Mars upper atmosphere, particularly for the horizontal internal gravity waves (hIGWs). In this study, the hIGWs in the upper atmosphere of Mars are estimated and investigated

We quantify the contributions of different convection states to the magnetic flux throughput of the magnetosphere during 2010. To do this we provide a continuous classification of convection state for the duration of 2010 based upon observations of the solar wind and interplanetary magnetic field, geomagnetic indices, and field‐aligned currents measured by the Active Magnetosphere and Planetary Electrodynamics

One of the grand challenge problems of the giant planet magnetospheres is the issue of non‐adiabatic plasma heating. Simple turbulent heating models consider the energy cascade rate from one scale to another where the energy density is based on perpendicular magnetic fluctuations of counter‐propagating Alfvén waves [Saur, 2004]. Analytical expressions from turbulence theory for the heating rate density

The dayside equatorial ionospheric electrodynamics exhibit strong variability driven simultaneously by highly changeable external forcings that originate from the solar EUV, magnetosphere, and lower atmosphere. We investigate this variability by carrying out comprehensive data‐driven ensemble modeling using a coupled model of the thermosphere and ionosphere, with the focus on the vertical E ×B drift