Survey of conditions for artificial aurora experiments by the second electron gyro-harmonic at EISCAT Tromsø using dynasonde data

Abstract

We report a brief survey of matching conditions for artificial aurora optical experiments utilizing the second electron gyro-harmonic (2.7-MHz frequency) in F region heating with O-mode at the EISCAT Tromsø site using dynasonde data from 2000 to 2017. Our survey indicates the following: The possible conditions for successful artificial aurora experiments are concentrated on twilight hours in both evening and morning, compared with late night hours; the possible conditions appear in fall, winter, and spring, while there is no chance in summer, and the month-to-month variation among fall, winter, and spring is not so clear; the year-to-year variation is well correlated with the solar activity. These characteristics in the case of 2.7-MHz frequency are basically similar to those previously reported in the case of 4-MHz frequency. However, the number of days meeting the possible condition in the case of 2.7-MHz frequency is obviously large, compared with that in the case of 4-MHz frequency. In particular, unlike the 4-MHz frequency operation, the 2.7-MHz frequency operation can provide many chances for successful artificial aurora experiments even during the solar minimum.

Special issue “Recent Advances in MST and EISCAT/Ionospheric Studies – Special Issue of the Joint MST15 and EISCAT18 Meetings, May 2017”

“…However, the chances of possible observations are not high and mostly hopeless during the solar minimum period. In the following report (Tsuda et al 2018b), they surveyed the possibility of artificial aurora experiment if they can use 2.7 MHz radio wave for heating. They suggested that, by decreasing the frequency of the heating radio wave from 4 to 2.7 MHz, the chance of experiment is much larger and becomes possible even during the solar minimum period.…”