DOI: 10.1002/2017JA024532
Scopus记录号: 2-s2.0-85042464831
论文题名: A Generalized Equatorial Model for the Accelerating Solar Wind
作者: Tasnim S. ; Cairns I.H. ; Wheatland M.S.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 2 起始页码: 1061
结束页码: 1085
语种: 英语
英文关键词: acceleration of the solar wind
; deviation from corotation
; interplanetary magnetic field
; solar wind
英文摘要: A new theoretical model for the solar wind is developed that includes the wind's acceleration, conservation of angular momentum, deviations from corotation, and nonradial velocity and magnetic field components from an inner boundary (corresponding to the onset of the solar wind) to beyond 1 AU. The model uses a solution of the time-steady isothermal equation of motion to describe the acceleration and analytically predicts the Alfvénic critical radius. We fit the model to near-Earth observations of the Wind spacecraft during the solar rotation period of 1–27 August 2010. The resulting data-driven model demonstrates the existence of noncorotating, nonradial flows and fields from the inner boundary (r = rs) outward and predicts the magnetic field B = (Br,Bϕ), velocity v = (vr,vϕ), and density n(r,ϕ,t), which vary with heliocentric distance r, heliolatitude ϕ, and time t in a Sun-centered standard inertial plane. The description applies formally only in the equatorial plane. In a frame corotating with the Sun, the transformed velocity V’ and a field B’ are not parallel, resulting in an electric field with a component E’z along the z axis. The resulting E’ × B’ = E’ × B drift lies in the equatorial plane, while the ∇B and curvature drifts are out of the plane. Together these may lead to enhanced scattering/heating of sufficiently energetic particles. The model predicts that deviations δvϕ from corotation at the inner boundary are common, with δvϕ(rs,ϕs,ts) comparable to the transverse velocities due to granulation and supergranulation motions. Abrupt changes in δvϕ(rs,ϕs,ts) are interpreted in terms of converging and diverging flows at the cell boundaries and centers, respectively. Large-scale variations in the predicted angular momentum demonstrate that the solar wind can drive vorticity and turbulence from near the Sun to 1 AU and beyond. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114620
Appears in Collections: 气候减缓与适应
There are no files associated with this item.
作者单位: School of Physics, The University of Sydney, Sydney, NSW, Australia
Recommended Citation:
Tasnim S.,Cairns I.H.,Wheatland M.S.. A Generalized Equatorial Model for the Accelerating Solar Wind[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(2)