Thursday, June 24, 2021

Jargon for solar-flares

I am making sense of BT Tsurutani et al. "A brief review of ‘‘solar flare effects’’ on the ionosphere" (2009). That's DOI 10.1029/2008RS004029.

This is in the genre of Jargon Update. Another example of the form would be McConaghy / Russell / Longuski, "Toward a Standard Nomenclature for Earth–Mars Cycler Trajectories" (2005). Which topic I'd burned out on - I mean, for an amateur like myself, or like Charles Murray for that matter, learning how to Kepler be quite enough fun for a month. But for solar-mass-eruptions I have been trying to be a professional. Or at least to fool the professionals sufficiently, as Turing's Monster could in theory fool Alan Turing.

As best I can interpret Tsurutani-plus, we all should be smarter about how we describe SFEs. That "E" part is for "effect" but, really, for "Earth". Solar flares do pound out some impressive radiation directly, but - per Tsurutani - that's not all they emit. These flareups also hit stray protons and other ions in the stellar corona, like that which your humble blogger witnessed up in Wyoming four summers back. This knock-on effect delivers mass with its energy: the ions get boosted to 10-10000 keV. Such behaves differently over here than the direct radiation spike behaves; more like cosmic rays.

So: the Interplanetary Coronal Mass Ejection. "Interplanetary" because such particles get kicked out from 3-10 stellar-radii (R☉) away from the star. For reference in our system Venus is 154.55, then Earth 218.57 R☉. "Interplanetary" seems overblown for something that's pretty-much still in the Solar exosphere, but hey: we give "astronaut" badges to LEO technicians. So why not.

Anyway, for my purpose, which is stray references to aurora AD 774 (and 664/3 BC), I am unsure that the base (ancient) documentation offers sufficient detail to decide if an aurora comes from the initial solar flux or from the heavy "interplanetary" particles afterward pushed this way secondarily.

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