Observations of the 3D distributions of thermal to near-relativistic electrons in the interplanetary medium by the wind spacecraft

2008 ◽  
pp. 93-107 ◽  
Author(s):  
Robert P. Lin
Keyword(s):  
Interplanetary Medium ◽  
Relativistic Electrons ◽  
Wind Spacecraft

scholarly journals Interpretation of increased energetic particle flux measurements by SEPT aboard the STEREO spacecraft and contamination

2018 ◽  
Vol 611 ◽  
pp. A100 ◽  
Author(s):  
S. Wraase ◽  
B. Heber ◽  
S. Böttcher ◽  
R. Bucik ◽  
N. Dresing ◽  
...  
Keyword(s):  
Energetic Particle ◽  
Particle Flux ◽  
Interplanetary Medium ◽  
Relativistic Electrons ◽  
Response Functions ◽  
Flux Measurements ◽  
Energetic Particle Flux ◽  
Flux Increase ◽  
Good Agreement

Context. Interplanetary (IP) shocks are known to be accelerators of energetic charged particles observed in-situ in the heliosphere. However, the acceleration of near-relativistic electrons by shocks in the interplanetary medium is often questioned. On 9 August 2011 a corotating interaction region (CIR) passed STEREO B (STB), which resulted in a flux increase in the electron and ion channels of the Solar Electron and Proton Telescope (SEPT). Because electron measurements in the few keV to several 100 keV range rely on the so-called magnet foil technique, which is utilized by SEPT, ions can contribute to the electron channels. Aim. We aim to investigate whether the flux increase in the electron channels of SEPT during the CIR event on 9 August 2011 is caused by ion contamination only. Methods. We compute the SEPT response functions for protons and helium utilizing an updated GEANT4 model of SEPT. The CIR energetic particle ion spectra for protons and helium are assumed to follow a Band function in energy per nucleon with a constant helium to proton ratio. Results. Our analysis leads to a helium to proton ratio of 16.9% and a proton flux following a Band function with the parameters I0 = 1.24 × 104 (cm2 s sr MeV nuc−1)−1, Ec = 79 keV nuc−1, and spectral indices of γ1 = −0.94 and γ2 = −3.80, which are in good agreement with measurements by the Suprathermal Ion Telescope (SIT) aboard STB. Conclusions. Since our results explain the SEPT measurements, we conclude that no significant amount of electrons were accelerated between 55 and 425 keV by the CIR.

scholarly journals Bootstrap energization of relativistic electrons in magnetized plasmas

2008 ◽  
Vol 4 (S257) ◽  
pp. 457-463
Author(s):  
Ilan Roth
Keyword(s):  
Electron Distribution ◽  
Radiation Belt ◽  
Interplanetary Medium ◽  
Small Scale ◽  
Relativistic Electrons ◽  
Whistler Waves ◽  
Outer Radiation Belt ◽  
Substorm Injection ◽  
Field Lines

AbstractIn situ and remote observations indicate that relativistic or ultra relativistic electrons are formed at various magnetized configurations. It is suggested that a specific bootstrap mechanism operates in some of these environments. The mechanism applies to (a) relativistic electrons observed on localized field lines in outer radiation belt - through a process initiated at a distant substorm injection; (b) relativistic electrons observed at the interplanetary medium - through a process initiated via coronal injection, at large distances from flares or propagating CME; (c) ultra-relativistic electrons deduced at the galactic jets - through a process initiated via local injection at the small-scale magnetic field. The injected nonisotropic electrons excite whistler waves which boost efficiently the tail of the electron distribution.

Instrumentation for detecting channelling radiation in the high-voltage electron microscope

1983 ◽  
Vol 41 ◽  
pp. 318-319
Author(s):  
J. H. Butler ◽  
C. J. Humphreys
Keyword(s):  
Monochromatic Light ◽  
Incident Beam ◽  
Laboratory Frame ◽  
Relativistic Electrons ◽  
Voltage Electron ◽  
Dipole Emission ◽  
Sinusoidal Oscillations ◽  
Pass Through ◽  
Incident Beam Energy ◽  
Increasing Function

Electromagnetic radiation is emitted when fast (relativistic) electrons pass through crystal targets which are oriented in a preferential (channelling) direction with respect to the incident beam. In the classical sense, the electrons perform sinusoidal oscillations as they propagate through the crystal (as illustrated in Fig. 1 for the case of planar channelling). When viewed in the electron rest frame, this motion, a result of successive Bragg reflections, gives rise to familiar dipole emission. In the laboratory frame, the radiation is seen to be of a higher energy (because of the Doppler shift) and is also compressed into a narrower cone of emission (due to the relativistic “searchlight” effect). The energy and yield of this monochromatic light is a continuously increasing function of the incident beam energy and, for beam energies of 1 MeV and higher, it occurs in the x-ray and γ-ray regions of the spectrum. Consequently, much interest has been expressed in regard to the use of this phenomenon as the basis for fabricating a coherent, tunable radiation source.

Radiation from relativistic electrons in a magnetic undulator

1989 ◽  
Vol 157 (3) ◽  
pp. 389 ◽  
Author(s):  
D.F. Alferov ◽  
Yu.A. Bashmakov ◽  
P.A. Cherenkov
Keyword(s):  
Relativistic Electrons ◽  
Magnetic Undulator

High resolution, single shot emittance measurement of relativistic electrons from laser-driven accelerator

2011 ◽  
Author(s):  
G. G. Manahan ◽  
E. Brunetti ◽  
R. P. Shanks ◽  
M. R. Islam ◽  
B. Ersfeld ◽  
...  
Keyword(s):  
High Resolution ◽  
Relativistic Electrons ◽  
Single Shot ◽  
Resolution Single ◽  
Emittance Measurement

scholarly journals High-sensitivity radio study of the non-thermal stellar bow shock EB27

2021 ◽  
Author(s):  
Paula Benaglia ◽  
Santiago del Palacio ◽  
Christopher Hales ◽  
Marcelo E Colazo
Keyword(s):  
Radio Emission ◽  
Massive Star ◽  
High Sensitivity ◽  
Bow Shock ◽  
Relativistic Electrons ◽  
Polarimetric Observation ◽  
Very Large Array ◽  
Thermal Radio Emission ◽  
The Magnetic Field ◽  
Linear Polarisation

Abstract We present a deep radio-polarimetric observation of the stellar bow shock EB27 associated to the massive star BD+43○3654. This is the only stellar bow shock confirmed to have non-thermal radio emission. We used the Jansky Very Large Array in S band (2–4 GHz) to test whether this synchrotron emission is polarised. The unprecedented sensitivity achieved allowed us to map even the fainter regions of the bow shock, revealing that the more diffuse emission is steeper and the bow shock brighter than previously reported. No linear polarisation is detected in the bow shock above 0.5%, although we detected polarised emission from two southern sources, probably extragalactic in nature. We modeled the intensity and morphology of the radio emission to better constrain the magnetic field and injected power in relativistic electrons. Finally, we derived a set of more precise parameters for the system EB27–BD+43○3654 using Gaia Early Data Release 3, including the spatial velocity. The new trajectory, back in time, intersects the core of the Cyg OB2 association.

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