The Case for Combining a Large Low‐Band Very High Frequency Transmitter With Multiple Receiving Arrays for Geospace Research: A Geospace Radar

Abstract

We argue that combining a high‐power, large‐aperture radar transmitter with several large‐aperture receiving arrays to make a geospace radar—a radar capable of probing near‐Earth space from the upper troposphere through to the solar corona—would transform geospace research. We review the emergence of incoherent scatter radar in the 1960s as an agent that unified early, pioneering research in geospace in a common theoretical, experimental, and instrumental framework, and we suggest that a geospace radar would have a similar effect on future developments in space weather research. We then discuss recent developments in radio‐array technology that could be exploited in the development of a geospace radar with new or substantially improved capabilities compared to the radars in use presently. A number of applications for a geospace radar with the new and improved capabilities are reviewed including studies of meteor echoes, mesospheric and stratospheric turbulence, ionospheric flows, plasmaspheric and ionospheric irregularities, and reflection from the solar corona and coronal mass ejections. We conclude with a summary of technical requirements.

Science goals for a high-frequency radar and radio imaging array

“…Ionospheric radar and radio imaging in the high-frequency band will motivate the development of techniques to quantify and correct for radio propagation effects, including refraction and reflection near the critical plasma level. These techniques will be valuable whenever renewed radar observations of the solar corona might be performed using VHF radar imaging at the critical plasma level in the corona (James, 1970;Hysell et al, 2019).…”

An Advanced Low-Band VHF Radar for Atmospheric, Geospace, and Solar Research

“…A low-band VHF geospace and heliospheric radar for atmospheric, space, and solar science has been a decades-long dream of atmospheric and space scientists, in part inspired by present and past radar observatories, including Jicamarca (50 MHz) (Ochs, 1965), Arecibo (40 MHz) (Mathews, 2013), and El Campo (38 MHz) (Abel et al, 1962). Efforts towards this goal have periodically been made (Thidé et al, 1994(Thidé et al, , 2002Hysell et al, 2019;Coster et al, 2021Coster et al, , 2022.…”

Feasibility analysis of optimal terahertz (THz) bands for passive limb sounding of middle and upper atmospheric wind

“…The coupling between the atmosphere and ionosphere is greatly influenced by the complex characteristics of the upper stratosphere and the mesosphere and lower thermosphere (MLT). However, measurements of wind speeds are still lacking in these altitude regions, particularly between 30 and 60 km, which is also known as the "radar gap" (Shepherd, 2015;Hysell et al, 2019;Liu et al, 2023).…”