Solar wind temperature and speed
Abstract
When it is averaged on a time scale of several solar rotations, the solar wind proton temperature T increases monotonically with the bulk speed V (Hundhausen et al., 1970; Burlaga and Ogilvie, 1970). This macroscale T-V relation does not change appreciably with solar cycle. The temperatures corresponding to intervals of increasing speed are only ≈15% higher than those corresponding to decreasing speeds, and thus it is indicated that the macroscale T-V relation is not appreciably affected by stream interactions. On a time scale of a tenth of a solar rotation there are time dependent T(t)-V(t) relations that are closely related to the stream profiles, as was noted by Hundhausen (1973). These T(t)-V(t) relations can meaningfully be resolved into two components—the macroscale T-V relation and systematic time dependent deviations from the macroscale relation. These results support the view that the macroscale T-V relation is not appreciably affected by nonsteady interplanetary processes but is determined rather by the proton heating mechanism within ≈50 RS. The systematic time dependent deviations between temperatures measured at streams and those given by the macroscale T-V relation are probably due primarily to nonlinear nonsteady processes in the interplanetary medium.
- Publication:
-
Journal of Geophysical Research
- Pub Date:
- 1973
- DOI:
- 10.1029/JA078i013p02028
- Bibcode:
- 1973JGR....78.2028B
- Keywords:
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- Particles and Fields-Interplanetary Space: General or miscellaneous