.
.
Professor says it’s “a giant feedback loop in space.”
Sept. 20, 2021: No solar storms? No problem. Earth has learned to make its own auroras. New results from NASA’s THEMIS-ARTEMIS spacecraft show that a type of Northern Lights called “diffuse auroras” comes from our own planet–no solar storms required.
Diffuse auroras look a bit like pea soup. They spread across the sky in a dim green haze, sometimes rippling as if stirred by a spoon. They’re not as flamboyant as auroras caused by solar storms. Nevertheless, they are important because they represent a whopping 75% of the energy input into Earth’s upper atmosphere at night. Researchers have been struggling to understand them for decades.
“We believe we have found the energy source for these auroras,” says UCLA space physicist Xu Zhang, lead author of papers reporting the results in the Journal of Geophysical Research: Space…
View original post 262 more words
Tallbloke's Talkshop 
The second study link at the end of the article (‘here’) doesn’t work due to ‘s’ at the end, should be:
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JA028743
Title: Beam-Driven Electron Cyclotron Harmonic Waves in Earth’s Magnetotail
Lunisolar shaping of geophysical records is not immaterial, nor is it homogeneous.
“Solar” proxies are (ever-so discretely) misinterpreted.
“According to Angelopoulos, Earth’s polar electron beams sometimes weaken but they never completely go away, not even during periods of low solar activity.”
So if they account for 75% of energy input into the upper atmosphere at night and can be quite variable, then energy input into the upper atmosphere at night must quite variable.
So does that affect night time temperatures?
Written > 20 years ago…
POLAR Scientists Discover the Energy Source Powering the Aurora
John Wygant , University of Minnesota
https://pwg.gsfc.nasa.gov/istp/polar/2000sept.html
Alfven waves to the fore.
SEPTEMBER 21, 2021
Could low-altitude reconnection power Jupiter’s polar aurorae?
by Morgan Rehnberg, American Geophysical Union
https://phys.org/news/2021-09-low-altitude-reconnection-power-jupiter-polar.html
– – –
Speculative modelling.
SOLAR SECTOR BOUNDARY CROSSING
23/09/21
Yesterday, Earth passed through a fold in the heliospheric current sheet–a vast wavy structure in interplanetary space separating regions of opposite magnetic polarity. Researchers call this a “solar sector boundary crossing” (SSBC), and here is what it did:
https://spaceweather.com/archive.php?view=1&day=23&month=09&year=2021