The Case for Improving the Robinson Formulas

Abstract

Auroral particle precipitation is the main source of ionization on the nightside, making it a critical factor in geospace physics. This magnetosphere-ionosphere linkage directly contributes to, even controls, the nonlinear feedback within this coupled system. One study has dominated our understanding of this connection, presenting a pair of equations relating auroral particle precipitation to ionospheric Pedersen and Hall conductance, the famous Robinson formulas. This Commentary examines the history of the development and usage of the Robinson formulas and the recent studies exploring corrections and expansions to it. The conclusion is that more work needs to be done; the space physics research community should take up the task to develop improvements and enhancements to better quantify the connection of auroral precipitation to ionospheric conductance. Other MHD calculations adopted a different approach. For example, Ridley et al. (2004) used a month of output from the assimilative mapping of ionospheric electrodynamics (AMIE) model to relate field-aligned

Why Atmospheric Backscatter Is Important in the Formation of Electron Precipitation in the Diffuse Aurora

“…The superposition of several monoenergetic spectra from 1 to 30 keV would provide further enhancement to the electron flux at energies below 1 keV. These results clearly demonstrate the dramatic role of the energy cascading processes in the formation of electron precipitation that was missing in the discussion by Liemohn (2020).…”

“…Ignoring both, the secondary electron production and the cascading processes of primary and secondary electrons (case NSC) completely removes the low energy part of the spectra from the simulation results leaving only the energy domain of the injected primary magnetospheric electrons above of 400 eV. This is the scenario that corresponds to the discussion presented by Liemohn (2020) in his formulas ( 3) and ( 4) when the nonelastic processes are completely ignored from consideration.…”

Testing the electrodynamic method to derive height-integrated ionospheric conductances

“…The original measurements contain fluctuations at various frequencies, with the most rapid fluctuations, lasting a few seconds or so, often having the largest magnitudes. Examples of these fluctuations can be seen in the recent comparison by Lomidze et al (2019), showing electric field measurements from the Swarm satellites compared with values from the earlier potential model (Weimer, 2005b). The end-result models are global-scale spatial representations of the fields that do not include such rapid fluctuations.…”

“…We use an updated electric potential model by Edwards (2019), which supplements the database from the Dynamics Explorer 2 spacecraft that was used by Weimer (2005b) with a substantially larger number of measurements from the Swarm spacecraft (Lomidze et al, 2019). Previous models had derived the least-error fit of the model coefficients from electric potentials that were obtained by integrating the measured electric field values along the satellite's path during each polar pass.…”

ASHLEY: A New Empirical Model for the High‐Latitude Electron Precipitation and Electric Field

“…Joule heating in GCMs is calculated from the electric field, conductivities associated with the solar ionization and electron precipitation together with the neutral winds (e.g., Lu et al., 1995). However, accurate estimations of Joule heating is still challenging to date since it is difficult to capture the dynamic variations of the electric field, ionospheric conductivity (mostly associated with the electron precipitation), and neutral winds (e.g., Billet et al., 2018; Liemohn, 2020; Pedatella et al., 2018). In this study, we focus on the improvements of the electric field and electron precipitation in GCMs.…”