High‐Latitude Plasma Convection Based on SuperDARN Observations and the Locally Divergence Free Criterion. Issue 12 (23rd December 2022)

• Record Type: Journal Article
• Authors: Bristow, W. A.; Lyons, L. R.; Nishimura, Y.; Shepherd, S. G.; Donovan, E. F.
• Is Part Of: Journal of geophysical research. Volume 127:Issue 12(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-23
• Subjects: magnetospheric convection -- convection pattern estimation; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2022JA030883
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: A new technique for estimating the global‐scale pattern of magnetospheric convection in the ionosphere is presented. The technique uses the Super Dual Auroral Radar Network line‐of‐sight velocity observations combined with an empirical convection model and the assumption that the resulting velocity field is divergence free. In contrast to other techniques for convection estimation, it does not express the velocity field in terms of known basis vectors and it does not assume that the velocity can be determined from a static potential. The velocity is estimated by applying Bayesian inverse theory to the input data, model, and constraints. Linear equations for the plasma velocity at every point in the domain are solved simultaneously in a least squares sense. Application of the technique results in convection patterns with spatial resolution equal to the calculation grid spacing. The resulting patterns conform with expectations based on the observed interplanetary magnetic field conditions and display features that show close correspondence to simultaneously observed features in the auroral luminosity. Plain Language Summary: A new technique for estimating the global‐scale pattern of plasma flow in the ionosphere is presented. The technique uses radar observations from a network of radars called the Super Dual Radar Network or Super Dual Auroral Radar Network. The observations are combined with a model that gives average patterns for the conditions at the time of the observations and some assumptions about the nature of the flow velocity to produce global‐scale patterns. The results will be useful for other studies of the magnetosphere, ionosphere, and upper atmosphere where understanding how the plasma moves is important. Key Points: Development of a new technique for estimating flow in the ionosphere The new technique provides high‐resolution estimates of the flows The flows show good correlation with the auroral luminosity