Magnetospheric banded chorus is enhanced whistler waves with frequencies

Using 2 Hz magnetic field data from the MESSENGER mission, we have investigated more than 300 strong narrowband ion cyclotron wave (ICW) events at a heliocentric distance of about 0.3 AU during 31 May to 9 June 2008. These nearly circularly polarized transverse waves are observed extensively and discretely in solar wind, with median duration 21 s. They preferentially when is radial ambient wind. The appear both left‐handed right‐handed spacecraft frame. Their frequencies frame generally...

Strongly localized, propagating plasma density structures that are capable of crossing magnetic field lines known as "blobs." Here we demonstrate a novel mechanism for the formation and propagation an ion gyroradius-scale blob-cavity structure at interface between super-Alfvénic laser-produced (LPP) ambient magnetized plasma. The LPP self-focuses along edge diamagnetic cavity which results in dense, jetlike compared to ballistic motion. This collimated flow couples momentum through...

Electromagnetic ion cyclotron (EMIC) waves in the Earth’s inner magnetosphere are driven by ring current ions and play an essential role electron dynamics. Since their frequency ranges (0.1 ~ 10 Hz) close to frequencies of protons (H+), singly ionized helium oxygen (He+, O+), they can efficiently heat cold via resonance. In this study, we run a hybrid simulation homogeneous plasma including hot H+ (~100 keV) H+, He+, O+, investigate EMIC wave properties after saturation associated...

Two‐dimensional hybrid (kinetic ions and massless fluid electrons) simulations of the Kelvin‐Helmholtz instability (KHI) for a magnetopause configuration with varying density jump magnetic shear across boundary are carried out to examine how transport magnetosheath plasma into magnetosphere is affected by these conditions. Low conditions where field within 30° northward included in because KHI thought be important only or near‐northward interplanetary orientations. The show that coherent...

An ongoing problem in heliospheric physics is the mechanism for heating and acceleration of solar wind. One process that has been identified as a potentially important source energy input ion cyclotron waves, but except some evidence perpendicular heavy ions obtained by remote sensing, it proven difficult to establish their overall effectiveness. We suggest mirror mode waves wind may be signature presence these corona. Mirror can cogenerated anisotropic distribution functions demonstrated...

This study reports direct detection by the Cassini plasma spectrometer of freshly‐produced water‐group pick‐up ions within proposed Enceladus torus, a radially narrow toroidal region surrounding Saturn that contains high density neutrals. torus is produced icy plumes observed near south pole Enceladus. The are created charge exchange collisions between neutrals in and thermal corotating with Saturn. They identified data via their characteristic ring‐like signatures ion velocity...

This paper describes the self‐consistent simulation of plasma transport across magnetic field at magnetopause driven by Kelvin‐Helmholtz (KH) instability. Two‐dimensional hybrid (kinetic ions, fluid electrons) simulations most KH‐unstable configuration where shear flow is oriented perpendicular to uniform are carried out. The motion particles tracked during run in order calculate their mean‐square displacement normal initial surface, from which diffusion coefficients may be determined. found...

Abstract Geoelectromagnetic disturbances (GMDs) are an important consequence of space weather that can directly impact many types terrestrial infrastructure. In this paper, we analyze 30 years SuperMAG magnetometer data from the range magnetic latitudes 20°≤ λ ≤75° to derive characteristic latitudinal profiles for median GMD amplitudes. Based on data, obtain a parameterization these different GMDs, providing analytical fit with D s t ‐dependent parameters. We also probabilistic estimates...

Abstract We compared the performance of DREAM3D simulations in reproducing long‐term radiation belt dynamics observed by Van Allen Probes over entire year 2017 with various boundary conditions (BCs) and model inputs. Specifically, we investigated effects three different outer conditions, two low‐energy for seed electrons, four radial diffusion (RD) coefficients ( D LL ), hiss wave models, chorus models from literature. Using condition driven GOES data, our benchmark simulation generally well...

Collisionless shocks are common phenomena in space and astrophysical systems, many cases, the can be modeled as result of expansion a magnetic piston though magnetized ambient plasma. Only recently, however, have laser facilities diagnostic capabilities evolved sufficiently to allow detailed study laboratory microphysics piston-driven shocks. We review experiments on collisionless driven by laser-produced undertaken with Phoenix Large Plasma Device at University California, Los Angeles. The...

Abstract The sudden loss of energetic protons in the inner radiation belt has been observed during geomagnetic storms. It is hypothesized that this occurs because changes field configuration which lead to a breakdown first adiabatic invariant, μ , process called magnetic line curvature scattering or scattering. Comparison observations various analytic model predictions for induced has, however, yielded discrepancies. To better understand how well models predict proton loss, test particle...

Abstract Electromagnetic ion cyclotron (EMIC) waves in the Earth's inner magnetosphere are enhanced fluctuations driven unstable by ring current temperature anisotropy. EMIC can resonate with relativistic electrons and play an important role precipitation of MeV radiation belt electrons. In this paper, we investigate excitation saturation instability a homogeneous plasma using both linear theory nonlinear hybrid simulations. We have explored four‐dimensional parameter space, carried out...

Abstract Ion cyclotron waves (ICWs) are generated during the interaction between solar wind and Martian exosphere in a process called ion pickup. Mars Global Surveyor (MGS) detected near proton gyrofrequency, indicating pickup of exospheric hydrogen. To analyze these waves, we first improve zero levels MGS magnetic field data taken aerobreaking phase then perform statistical study ICWs observed from just outside bow shock to over 14 radii away. These ICW events typically last for 5 30 min...

Observations upstream of Mars show strong and persistent plasma wave activity near the local proton cyclotron frequency. These waves are thought to be generated by unstable populations newborn ions produced ionization Martian hydrogen exosphere. It is generally believed that amplitudes related energy pickup ion population, such observed spatial temporal distribution could used as a diagnostic exospheric structure loss rate. To understand relationship between rate, we carry out parametric...

The coupling between a rapidly expanding cloud of ionized debris and an ambient magnetized plasma is revisited with hybrid (kinetic ion/fluid electron) simulation code that allows study over wide range parameters. Over specified hypothetical conditions, simple scaling laws in terms the total mass explosion speed are derived verified for maximal size fraction free-streams from burst along magnetic field. amount escapes minimal to background field increases gyroradius. Test cases two different...

Abstract Linear instability analysis as well a corresponding two‐dimensional hybrid simulation are performed to examine the excitation of proton cyclotron waves observed upstream Mars. The believed be excited by pickup ions produced from ionization Martian hydrogen exosphere. And previous statistical wave observations suggested that mostly related ion beam velocity distributions. While earlier linear distributions has mainly been focused on parallel unstable modes, our reveals maximum growth...

Recent Cassini observations of active venting water molecules from Enceladus indicate that the moon is primary source Saturn's extended neutral cloud. Ionization neutrals through charge exchange creates a population newborn ions with velocity space distribution, which highly unstable to generation electromagnetic ion cyclotron waves. observed such waves, finding spatial and temporal variability in wave amplitudes throughout cloud region. Since amount energy waves proportional number...

Titan's dense atmosphere is thought to be an important source of pickup ions in the Saturnian magnetosphere. Cassini spacecraft measurements plasmas near Titan show evidence ions, yet electromagnetic ion cyclotron waves, which are direct indicators pickup, have not been detected. Pickup and their associated waves observed at Saturn's Extended Neutral Cloud (∼4–10 R s ), as well Jupiter's moon, Io, suggesting that plasma conditions may fundamentally different than these other environments....

Ion pickup in planetary environments results unstable newborn ion populations with sufficient free energy to generate electromagnetic plasma waves. Estimates of the SO 2 + rates near Jovian moon, Io, based on cyclotron wave observations assumed that ions lose 50% their growth. Using one‐dimensional initial‐value hybrid simulation, we test this assumption and predict at most ∼25% population is lost growth for conditions Io. This over >1400 gyroperiods (∼1 hour), majority after saturation...

The one‐dimensional hybrid simulation technique using massless fluid electrons and kinetic ions has been shown to successfully reproduce the growth of electromagnetic plasma waves generated by ion populations with a ring velocity distributions ( T ⊥ > ∥ ). Such are found at Jupiter Saturn, where newborn picked up into corotating flows that nearly perpendicular background magnetic field. In previous work, which focused on pickup near Io, we considered all be present in start run (initial...

Abstract In the vicinity of Europa, Galileo observed bursty Alfvén‐cyclotron wave power at gyrofrequencies a number species including K + , O Na and Cl indicating localized pickup these species. Additional evidence for presence chlorine was occurrence both left‐hand (LH) right‐hand (RH) polarized transverse near gyrofrequency, thought to be due easily formed anion, − . To test this hypothesis, we use one‐dimensional hybrid (kinetic ion, massless fluid electron) simulations positive negative...

Abstract Proton cyclotron waves (PCWs) upstream of Mars are thought to be associated with the instabilities pickup ions. The ions ring distributions have larger maximum growth rates compared beam distributions. However, observations revealed a notably‐reduced occurrence rate PCWs for Linear instability analysis and corresponding two‐dimensional particle‐in‐cell (PIC) simulation performed investigate ion Mars. indicates that distribution is unstable cyclotron, Bernstein, mirror instabilities....

Enhanced electromagnetic plasma waves generated by unstable pickup ion distributions have been detected spacecraft in several planetary environments including those of Venus, Earth, Mars, comets, Jupiter and Saturn. These are important because they can be used as a diagnostic the local conditions. Interpretation these relies on understanding source free energy how that is reduced through instability growth. In this manuscript, we focus regime where velocity sub‐Alfvénic systematically...