Direct determination of IMF B_Y‐related cusp current systems, using SuperDARN radar and multiple ground magnetometer data: A link to theory on cusp current origin

Abstract

Abstract. We analyze an ionospheric "enhanced convection event" in the cusp on November 13, 1996, at 1900 UT, by using data of the SuperDARN radar, and of the IMAGE, Greenland, MACCS and CANOPUS magnetometer arrays; and from other magnetometer stations. The event occurs -20 minutes after a transition of the IMF By component from positive to negative and an associated reconfiguration of the ionospheric electric potential pattern. The data allow an instantaneous two-dimensional view of the event in terms of the ionospheric electric and ground magnetic field. The "method of characteristics" is used to obtain distributions of ionospheric conductances, actual ionospheric currents, and field-aligned currents (FACs) for the interval under study. Our results show that the region of enhanced convection observed by the radar is associated with a region of low conductances, ranging only slightly above the UV conductance values.However, owing to the strongly enhanced electric field, it produces enhanced westward flowing

A decade of the Super Dual Auroral Radar Network (SuperDARN): scientific achievements, new techniques and future directions

“…Hence, the measurements of the electric field and conductance in this technique are not truly independent. Amm et al (1999) used this technique to examine the time development of ionospheric convection and FAC patterns following an IMF B y transition. They associated a region of enhanced convection observed by SuperDARN in the noon/early afternoon sector with a region of low conductance.…”

“…Generally, it is extremely difficult to measure, or to accurately model, spatiotemporal variations in ionospheric conductance and hence, measurements of this type are rare. Amm et al (1999) combined SuperDARN convection maps and ground-based magnetometer data to measure FACs using the Method of Characteristics (Inhester et al 1992). This method combines measurements of ionospheric equivalent currents, determined from ground magnetic variations, with the ionospheric electric field, in order to determine the Hall conductance distribution.…”

Height‐integrated Joule and auroral particle heating in the night side high latitude thermosphere

“…[6] TIMED GUVI is a cross-track scanning spectrometer that measures auroral emission at five ultra-violet ''colors'' [Christensen et al, 2003]. Emissions at two wavelengths in the Lyman-Birge-Hopfield (LBH) N 2 bands can be combined with auroral modeling to estimate Q P and the average energy, e, of auroral precipitation [Germany et al, 1994].…”

“…[4] Several studies have investigated height-integrated Joule heating using data from distributed magnetometer arrays and/or radars [e.g., Vickrey et al, 1982;Lu et al, 1995;Amm et al, 1999]. In this letter, SuperDARN and TIMED GUVI data are used to calculate Q C .…”

Assessing the contamination of SuperDARN global convection maps by non-F-region backscatter

“…Global convection mapping using data from the Super Dual Auroral Radar Network (SuperDARN), as pioneered by Ruohoniemi and Baker (1998), is fast becoming a significant tool for imaging high-latitude ionospheric convection. This method has been used to study the large-scale global nature of convection (Amm et al, 1999;Shepherd et al, 1999;Shepherd and Ruohoniemi, 2000), and it is increasingly being used to study local, mesoscale variations Huang et al, 2000), and transient features (Greenwald Correspondence to: G. Chisham (G.Chisham@bas.ac.uk) Neudegg et al, 2000) of the ionospheric convection pattern.…”