Proton Beams

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Proton beam forms a distinct shoulder in velocity space

Two stacked contour plots show particle velocity distributions in a coordinate system of parallel velocity (horizontal axis) versus perpendicular velocity (vertical axis), both in km/s. The top panel, labeled H+, displays protons as concentric filled contours ranging from red at the dense center through yellow, green, cyan, and blue outward. A clear elongation extends to the right at positive parallel velocities, forming a secondary shoulder -- the proton beam. Solid contour lines mark the densest regions and dashed circles trace the sparse outer edges. The bottom panel, labeled He++, shows alpha particles as a single compact oval of similarly colored contours, slightly offset from the origin in the positive parallel direction.

velocity_distribution_functionproton_beamalpha_particleproton_corevelocity_spacebeam_shoulderfield_aligned_driftphase_space_density

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Source

A Comparison of Alpha Particle and Proton Beam Differential Flows in Collisionally Young Solar Wind

The Astrophysical Journal (2018)

View Paper