Rights statement: ©2013. American Geophysical Union
Final published version, 213 KB, PDF document
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - An indication of the existence of a solar wind strahl at 10AU
AU - Walsh, A. P.
AU - Arridge, C. S.
AU - Masters, A.
AU - Lewis, Gethyn. R.
AU - Fazakerley, A. N.
AU - Jones, Geraint. H.
AU - Owen, C. J.
AU - Coates, A. J.
N1 - ©2013. American Geophysical Union
PY - 2013/6/16
Y1 - 2013/6/16
N2 - The solar wind electron distribution is observed near and within 1AU to consist of three components: a thermal core, a suprathermal halo, and a suprathermal strahl. The former two components are isotropic, while the strahl is field aligned and flows outward along the interplanetary magnetic field. The evolution of solar wind electrons with heliocentric distance is poorly understood; although the halo is thought to be formed through pitch angle (PA) scattering of the strahl, the responsible physical process has not been conclusively identified. Measurements of solar wind electrons throughout the heliosphere are required to solve this problem. We present the first observations of the suprathermal components of the solar wind electron distribution made outside 5AU. We find indications of a strahl component narrower than that predicted by extrapolating observations and models of electrons in the inner heliosphere, suggesting the rate of electron pitch angle scattering in the solar wind can decrease with increasing heliocentric distance.
AB - The solar wind electron distribution is observed near and within 1AU to consist of three components: a thermal core, a suprathermal halo, and a suprathermal strahl. The former two components are isotropic, while the strahl is field aligned and flows outward along the interplanetary magnetic field. The evolution of solar wind electrons with heliocentric distance is poorly understood; although the halo is thought to be formed through pitch angle (PA) scattering of the strahl, the responsible physical process has not been conclusively identified. Measurements of solar wind electrons throughout the heliosphere are required to solve this problem. We present the first observations of the suprathermal components of the solar wind electron distribution made outside 5AU. We find indications of a strahl component narrower than that predicted by extrapolating observations and models of electrons in the inner heliosphere, suggesting the rate of electron pitch angle scattering in the solar wind can decrease with increasing heliocentric distance.
KW - solar wind
KW - electrons
KW - strahl
KW - heliosphere
KW - VELOCITY DISTRIBUTION-FUNCTIONS
KW - HELIOS PLASMA-EXPERIMENT
KW - ELECTRONS
KW - HALO
KW - SPECTROMETER
KW - WAVES
KW - AU
U2 - 10.1002/grl.50529
DO - 10.1002/grl.50529
M3 - Journal article
VL - 40
SP - 2495
EP - 2499
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 11
ER -