New EISCAT observations of large field‐aligned bulk ion outflows from the topside ionosphere during auroral activity are presented. The ions (mainly O+) start their outflows from a variable altitude and may reach field‐aligned outward velocities of up to 1500 m s−1 in the altitude region 900–1500 km. The observed ion fluxes are about a factor of 10 larger than previously observed reaching 2×1014 m−2 s−1, and in some cases is nonconstant with altitude. Two different types of ion outflows have been identified. The first type is related to periods of strong perpendicular electric fields, enhanced and anisotropic ion temperatures, and low electron densities below 300 km, indicating small amounts of auroral precipitation. The second type is related to auroral arcs and enhanced electron temperatures. The exact mechanism causing the ion outflows is still not yet understood, but additional mechanisms other than thermal expansion are required to explain the observations presented here.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.