We employ 2.5‐D electromagnetic, hybrid simulations that treat ions kinetically via particle‐in‐cell methods and electrons as a massless fluid to study the formation properties of new structure named foreshock bubble upstream from bow shock. This forms due changes in interplanetary magnetic field (IMF) associated with solar wind discontinuities their interaction backstreaming prior these encountering The leading edge consists fast magnetosonic shock compressed heated plasma downstream...

Using multipoint in situ observations upstream of Earth's bow shock from the THEMIS mission, we present first foreshock bubbles (FBs) and compare them to hot flow anomalies (HFAs). FBs are recently conceptualized kinetic phenomena that can form under commonplace condition a rotational discontinuity interplanetary magnetic field interacting with backstreaming energetic ions quasi‐parallel foreshock. may have remained elusive until now due their many observational similarities HFAs lack...

We present Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations a “Spontaneous Hot Flow Anomaly” (SHFA) upstream from the prenoon bow shock at 0431 UT on 12 August 2007. Although SHFA exhibited greatly heated deflected solar wind plasmas used to identify hot flow anomalies (HFAs), it did not result standard mechanism invoked for formation HFAs, namely interaction an interplanetary magnetic field (IMF) discontinuity with shock. employ THEMIS A, B, C, D...

We use global hybrid (kinetic ions and fluid electrons) simulations to study the solar wind interaction with magnetosphere for a radial (θ vB = 0) interplanetary magnetic field (IMF) geometry. Global provide collective picture of processes taking place in foreshock, bow shock, magnetosheath. Because are treated as particles, these codes also give information on ion‐scale microphysics. Under IMF geometry, foreshock forms front dayside magnetosphere, plasma convecting downstream is very...

In fluid theory, the ordering of low‐frequency modes in a homogeneous plasma is based on phase velocity, since do not intersect each other dispersion diagrams as function wavenumber or parameters. linear kinetic cross other. Thus consistent and useful classification should be physical properties instead. This paper attempts such by documenting general mode waves (ω « (Ω ci Ω ce ) 1/2 , where are cyclotron frequencies ions electrons, respectively) comparing them to results two‐fluid theory....

Numerical simulations are used to investigate the nonlinear evolution of oblique low‐frequency electromagnetic (kinetic magnetosonic) waves, which have been observed upstream planetary bow shocks and at comet Giacobini‐Zinner. The observations show that waves elliptically polarized a sinusoidal form when their amplitude is small, but they become steepened linearly as grow in amplitude. These referred shocklets. A high‐frequency whistler wave packet commonly seen edge To generation kinetic...

Interaction of a tangential discontinuity (TD) with the bow shock is investigated by using electromagnetic, global hybrid simulations in which ions are treated kinetically via particle‐in‐cell methods and electrons form massless fluid. On basis previous studies, it was expected that interaction would result formation hot flow anomaly (HFA) propagating along curved surface. The results unexpected two major ways. First, only formed during TD quasi‐parallel side shock. lack HFA on perpendicular...

The relativistic cyclotron resonance condition for right‐handed extraordinary mode waves defines an ellipse in velocity space. position of the center and size semiminor axis this are functions plasma frequency, gyrofrequency, wave normal angle. effect varying these parameters on contour is analyzed. results show that as angle decreases, increases frequency to gyrofrequency ratio minimum energy resonating electrons decreases maximum allowed by increases. Also, increases, moves away from...

Abstract Motivated by recent THEMIS observations, this paper uses 2.5‐D electromagnetic hybrid simulations to investigate the formation of Spontaneous Hot Flow Anomalies (SHFAs) upstream quasi‐parallel bow shocks during steady solar wind conditions and in absence discontinuities. The results show a large number structures along shock. Their outer edges exhibit density magnetic field enhancements, while their cores drops density, field, velocity, enhancements ion temperature. Using virtual...

Transverse, near-circularly polarized, parallel-propagating electromagnetic waves around the proton cyclotron frequency were found sporadically in solar wind throughout inner heliosphere. They could play an important role heating and accelerating wind. These low-frequency (LFWs) are intermittent but often occur prolonged bursts lasting over 10 minutes, named "LFW storms." Through a comprehensive survey of them from Solar Terrestrial Relations Observatory A using dynamic spectral wave...

Abstract Spacecraft observations and global hybrid (kinetic ions fluid electrons) simulations have demonstrated that ion dissipation processes at the quasi‐parallel bow shock are associated with formation of structures called spontaneous hot flow anomalies (SHFAs). Previous recent spacecraft also established SHFAs result in magnetosheath filamentary (MFS). In this paper we demonstrate addition to MFS, cavities decreases density, velocity, magnetic field enhancements temperature. We use...

Plasmoids/flux ropes have been observed both at Earth's magnetopause as well in the magnetotail. Magnetic field measurements of such structures often reveal that rather than a minimum strength their centers expected from simple O‐type neutral line picture, they exhibit strong core field. To address this issue, two‐dimensional (2‐D) and 3‐D hybrid simulations are used to investigate magnetic structure reconnection layer general formation within plasmoids particular. The magnetotail is found...

Large‐scale, 2‐D hybrid simulations are used to investigate the ion kinetic physics associated with quasi steady‐state reconnection in magnetotail. The encompass a significant portion (20 × 120 R E ) of tail. After formation transient plasmoids, results show features fast Petschek‐type reconnection. There two pairs thin transition layers attached x ‐point which divert and accelerate flow within few inertial lengths. These do not quite conform properties expected slow shocks. reason for this...

This paper considers the linear theory of ion-acoustic-like instabilities in a homogeneous Vlasov plasma with two ion components, less dense beam and more core, relative drift velocity. Numerical solutions full electrostatic dispersion equation are presented, properties ion–ion acoustic instability studied detail. The following demonstrated: (i) At relatively cold temperatures, is fluid-like, but it becomes resonant kinetic as temperature order core temperature; (ii) if mode unstable, its...

One‐dimensional hybrid (particle ion, massless fluid electron) simulations of quasi‐parallel shocks and two stream interactions are carried out in order to study the mechanism by which large‐amplitude electromagnetic waves generated at shock maintained a quasi‐steady manner. It is concluded that resonant interaction interface between incoming ions heated downstream (“interface instability”) most likely source ultimately comprise shock. The effect generation these transition results locally...

Hybrid (particle ion, massless fluid electron) simulations are carried out in one and two spatial dimensions to show that the supercritical quasi‐parallel shock is not steady. Instead of a well‐defined narrow transition region (shock ramp) between upstream downstream states remains at fixed position flow, ramp periodically steepens, broadens, then re‐forms its former position. During part re‐formation cycle, number ions backstreaming from increases significant fraction (up 40%) incoming...

We perform global hybrid (kinetic ions and fluid electrons) simulations of the solar wind coupling with magnetic dipoles different strength study foreshock morphology its influence on bow shock magnetosheath. The advantage code over codes is that it treats ion‐scale microphysics in context interaction. characteristics ultralow‐frequency (ULF) waves generated by kinetic instabilities find two types waves: (1) sinusoidal almost parallel propagating (2) highly compressive obliquely...

The relativistic Doppler‐shifted cyclotron resonance condition for electromagnetic wave interactions with a plasma is studied. results indicate that the defines an ellipse in velocity space when product of index refraction and cosine normal angle less than or equal to 1 it partial larger 1. It also shown waves frequencies greater gyrofrequency (or its harmonic higher resonances) can only resonate particles moving same direction along magnetic field, while harmonic) both directions field....

[1] Global hybrid (kinetic ions, fluid electrons) simulations have shown the existence of foreshock cavitons characterized by large depressions in plasma density and magnetic field magnitude, bounded enhancements these two parameters. Foreshock share some characteristics with reported cavities, but contrast to cavities that often appear as isolated structures, are always found surrounded a sea ultra low frequency (ULF) waves. They occur regions deep foreshock, downstream from ion ULF wave...

We employ 2.5‐D electromagnetic, hybrid simulations that treat ions kinetically via particle‐in‐cell methods and electrons as a massless fluid to study the formation properties of newly discovered boundary named foreshock compressional (FCB). This forms in ion is associated with enhanced densities magnetic field strengths. At times, but not always, FCB separates pristine solar wind plasma from foreshock. In this study, we investigate dependence characteristics on Mach number cone angle (the...

Abstract This work presents the first detailed analysis of foreshock bubbles (FBs) using high‐resolution Magnetospheric Multiscale (MMS) data. Between October 2017 and January 2019, MMS captured 10 transient events with burst resolution data that we show are consistent FBs. One “textbook” event is examined described in detail. Employing multipoint nature MMS, demonstrate how size orientation, expansion speed, distance since formation can be estimated. From all events, FB sizes ranged from...

The basic concepts involved in formulating and analyzing simulations of kinetic space plasmas are presented for readers with little background simulation methods. Issues related to choosing the appropriate physics models numerical algorithms, such as correct representation plasma, proper description electromagnetic fields, geometric effects, initial boundary conditions, diagnostics, discussed. Some strengths limitations various approaches also described. Explicit examples involving...