Which solar activity proxies explain ionospheric variability at middle latitudes?

Using the fo F2 parameters of 11 ionospheric stations in four continents over 1976–2014, Laštovička and Burešová (2023) further found that among the six studied solar activity proxies including sunspot number, F10.7, F30, Mg II, He II, and H Lyman- α flux, the F30 flux is the best solar proxy to explain the variability of fo F2 at middle latitudes.

Is F30 a good solar proxy?

Danilov and Berbeneva (2024) also found that F30 is the best solar proxy to describe the seasonally dependent local-time variation of fo F2. When studying the performance of F10.7 and F30 as solar EUV proxies in the thermosphere and ionosphere, it is necessary to understand their origin and mutual relationship.

Why does the F30 Flux perform more consistently as a solar EUV proxy?

This differential long-term evolution in the solar atmosphere due to the weakening solar activity during the decay of the Modern Maximum may offer an explanation to why the F30 flux performs more consistently as a solar EUV proxy than the F10.7 flux.

Where is our Solar System situated?

Our solar system is located in the Milky Way, a barred spiral galaxy with two major arms and two minor arms. Our Sun is in a small, partial arm of the Milky Way called the Orion Arm, or Orion Spur, between the Sagittarius and Perseus arms. Our solar system orbits the center of the galaxy at about 515,000 mph (828,000 kph).