The neutral wind pattern over the summer polar cap can be driven by plasma convection to resemble the convection pattern. For a north‐south component of the interplanetary magnetic field Bz directed southward, the wind speeds in the conducting E‐region can become ∼ 25% of the electric field drift speeds. If convection ceases, this neutral wind distribution can drive a significant polar cap current system for ∼ 6 hours. The currents are reversed from those driven by the electric fields for southward Bz, and the Hall and field‐aligned components of the current system resemble those observed during periods of northward Bz. The current magnitudes are similar to those observed during periods of small, northward Bz; however observations indicate that electric fields often contribute to the currents as much as, or more than, the neutral winds.
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)