Relativistic Electrons Produced by Foreshock Disturbances Observed Upstream of Earth's Bow Shock.

  title={Relativistic Electrons Produced by Foreshock Disturbances Observed Upstream of Earth's Bow Shock.},
  author={Lynn Bruce Wilson and David Gary Sibeck and Drew L. Turner and Adnane Osmane and Damiano Caprioli and Vassilis Angelopoulos},
  journal={Physical review letters},
  volume={117 21},
Charged particles can be reflected and accelerated by strong (i.e., high Mach number) astrophysical collisionless shock waves, streaming away to form a foreshock region in communication with the shock. Foreshocks are primarily populated by suprathermal ions that can generate foreshock disturbances-large-scale (i.e., tens to thousands of thermal ion Larmor radii), transient (∼5-10  per day) structures. They have recently been found to accelerate ions to energies of several keV. Although… 
Relativistic electrons generated at Earth’s quasi-parallel bow shock
Using in situ observations at Earth’s bow shock, it is shown that relativistic electrons are generated by the interaction between the quasi-parallel shock and a related nonlinear structure, a foreshock transient, through two betatron accelerations.
Fermi acceleration of electrons inside foreshock transient cores
Foreshock transients upstream of Earth's bow shock have been recently observed to accelerate electrons to many times their thermal energy. How such acceleration occurs is unknown, however. Using Time
Statistical study of particle acceleration in the core of foreshock transients
Several types of foreshock transients upstream of Earth's bow shock possessing a tenuous, hot core have been observed and simulated. Because of the low dynamic pressure in their cores, these
Ion Acceleration Inside Foreshock Transients
Recent observations upstream of Earth's bow shock have revealed that foreshock transients can not only accelerate solar wind ions by reflection at their upstream boundaries but may also accelerate
Electron Resonant Interaction With Whistler Waves Around Foreshock Transients and the Bow Shock Behind the Terminator
Investigation of electron energization at (and around) the Earth's bow shock is critical to our understanding of space weather and astrophysical phenomena. The traditional adiabatic mechanisms for
An in situ Comparison of Electron Acceleration at Collisionless Shocks under Differing Upstream Magnetic Field Orientations
A leading explanation for the origin of Galactic cosmic rays is acceleration at high-Mach number shock waves in the collisionless plasma surrounding young supernova remnants. Evidence for this is
Autogenous and efficient acceleration of energetic ions upstream of Earth’s bow shock
Observations of a hot flow anomaly accelerating solar-wind ions suggest a mechanism for Fermi acceleration trap caused by Earth’s bow shock interacting with the solar wind, and implies that foreshock transients may be important in the generation of cosmic rays at astrophysical shocks throughout the cosmos.
Energetic ion leakage from foreshock transient cores
Earth's foreshock is filled with backstreaming particles that can interact with the ambient solar wind and its discontinuities to form foreshock transients. Many foreshock transients have a core with
Observational Evidence for Stochastic Shock Drift Acceleration of Electrons at the Earth's Bow Shock.
Direct evidence is presented for a novel stochastic shock drift acceleration theory for the injection obtained with Magnetospheric Multiscale observations at the Earth's bow shock, which may provide a solution to the long-standing issue of electron injection.
Magnetospheric Multiscale (MMS) Observations of Magnetic Reconnection in Foreshock Transients
Magnetic reconnection is a fundamental process of energy conversion in plasmas between electromagnetic fields and particles. Magnetic reconnection has been observed directly in a variety of plasmas


Electron Acceleration to Relativistic Energies at a Strong Quasi-Parallel Shock Wave
Electrons can be accelerated to ultrarelativistic energie s at strong (high-Mach number) collisionless shock waves that form when stellar debris rapidly expands af ter supernova [4, 2, 19].
Electron acceleration to non-thermal, ultra-relativistic energies (~10-100 TeV) is revealed by radio and X-ray observations of shocks in young supernova remnants (SNRs). The diffusive shock
Suprathermal electrons at Earth's bow shock
A hot, suprathermal population of electrons is often present near the Earth's bow shock. The overall morphology of this hot population as observed with the Los Alamos/Garching fast plasma experiments
Ion Acceleration at the Earth’s Bow Shock
The Earth’s bow shock is the most studied example of a collisionless shock in the solar system. It is also widely used to model or predict the behaviour at other astrophysical shock systems.
Particle-in-cell simulations of particle energization via shock drift acceleration from low Mach number quasi-perpendicular shocks in solar flares
Low Mach number, high beta fast mode shocks can occur in the magnetic reconnection outflows of solar flares. These shocks, which occur above flare loop tops, may provide the electron energization
Measurements of bow shock particles far upstream from the Earth
Electrons and ions moving upstream frequently appear at distances up to 240 RE from earth at times when the direction of the interplanetary magnetic field allows their propagation from the bow shock.
A fast Fermi process: Energetic electrons accelerated by a nearly perpendicular bow shock
The highly localized acceleration of electrons at the foreshock reported by Anderson et al. (1979) is explained in terms of a fast Fermi process. The basic notion is that in the solar wind frame the
Thin sheets of energetic electrons upstream from the earth's bow shock
ISEE spacecraft observations show that energetic, ≥ 16 keV electrons are injected into the region upstream from the Earth’s bow shock in a thin sheet which lies just behind the sheet of
Simulations of Ion Acceleration at Non-relativistic Shocks. I. Acceleration Efficiency
We use two-dimensional and three-dimensional hybrid (kinetic ions-fluid electrons) simulations to investigate particle acceleration and magnetic field amplification at non-relativistic astrophysical
Particle acceleration at coronal mass ejection–driven interplanetary shocks and the Earth's bow shock
[1] Particle acceleration in space plasmas, particularly at collisionless shocks, remains a fundamental yet poorly understood problem in space physics. The most important questions that need to be