Revisiting the Behavior of the E‐Region Electron Temperature During Strong Electric Field Events at High Latitudes

A rich data set acquired during a long‐lived strong electric field event by the north‐facing Resolute Bay incoherent scatter radar confirms and strengthens conclusions previously drawn from several less comprehensive studies of E‐region electron heating by large amplitude Farley‐Buneman waves. For the exceptionally abundant set of very good quality data we uncovered, the E‐region electron temperature response to strong ambient electric fields is described very accurately by a simple linear function of the electric field at 110 and 117 km altitudes. The linear dependence starts at 40 mV/m and shows no hint of deviating from the linear response up to 150 mV/m (the maximum electric field observed during this event). Based on this new evidence, we have revisited previous E‐region electron temperature observations from various altitudes and have built a model that is consistent with present and past observations. The model is made of simple linear variations in the electron temperature with slopes that depend on altitude. It should prove to be a useful reference for anyone interested in the E‐region electron temperature anywhere between 100 and 120 km altitudes. Plain Language Summary Below 120 km, ionospheric electrons collide so much with the background atmosphere that their temperature is normally the same as the atmospheric one. A notable exception is when auroral electric fields become large. Radars then show electronic temperatures that can then be up to 10 times the atmospheric. The only energy source known to produce these temperatures is electric fields partially aligned with the geomagnetic field in small turbulent structures created when the electrons become supersonic. Here, we document an event with exceptionally good radar signal and more strong electric field data than in any previous study. The data quality is so good that we can firmly state that the electron temperature is directly proportional to the electric field once their motion exceeds 800 m/s. From our new data set, we have revisited past publications and inferred detailed electron temperature profiles versus electric field. Our empirical model will allow researchers to better understand the evolution of the turbulent structures and their role in the aurora. Key Points A rich data set shows a strong tendency for a linear dependence of electron temperature versus electric field strength up to 150 mV/m A novel empirical model of electron temperature versus electric field strength is creat