3 ms·

https://www.researchgate.net/publication/3165629_Characteristics_for_the_Occurrence_of_a_High-Current_Z-Pinch_Aurora_as_Recorded_in_Antiquity https://www.resear

https://www.researchgate.net/publication/3165629_Characteristics_for_the_Occurrence_of_a_High-Current_Z-Pinch_Aurora_as_Recorded_in_Antiquity https://www.researchgate.net/publication/3165629_Characteris... I'm reading this critical analysis of it (2013): https://www.researchgate.net/publication/292848789_Geometry_of_an_Intense_Auroral_Column_As_Recorded_in_Rock_Art https://www.researchgate.net/publication/292848789_Geometry_... > The interpretation of individual rock art images and related art forms as local perspectives on a single celestial phenomenon requires a determination of scale, perspective, and temporal evolution. Peratt interpreted dotted circles and concentric circles as bottom-up renditions of a diocotron instability affecting the hollow outer sheets of the z-pinch (Peratt 2003:1209–1210,1212), while he derived ‘ladders’, ‘caterpillars’, ‘birds on sticks’, ‘squattermen’, ‘Kokopelli’, and many other forms from instabilities in the solid inner core of the lower segment of the auroral beam, viewed sideways or at an oblique angle (Peratt 2003:1193–1205). So far, so good— the matches between these respective instabilities and their petroglyphic correlates are indeed compelling. Problems appear when the geographic distribution of such designs is taken into account.

xattt 3y ago
I’m trying to understand what kind of phenomenon beams a column of light into the sky from the South Pole. I can understand auroral curtains, but a cylinder beam sounds far-fetched.
- michaelsbradley 3y ago
  Birkeland current
klondike_klive 3y ago
> Peratt interpreted dotted circles and concentric circles as bottom-up renditions of a diocotron instability affecting the hollow outer sheets of the z-pinch I love this sentence. I am pretty inarticulate in person, sometimes I fantasise myself delivering lines like this in a hastily erected mobile command centre. "In English, please, professor?" growls a FBI agent. My acolyte pushes their glasses up "uh... uh... if you consider these petroglyphs as a correlate of an instability in the solid inner core of the lower segment of the auroral-" the FBI agent pinches his temples and rounds on the eager young researcher, "You better start making sense, pencil-neck!" I step gently in between them "In simple terms, we're talking about... a Miyake Event."
- ambicapter 3y ago
  You're just a screenplay away from playing your dream self in a movie.
- HerculePoirot 3y ago
  Got some more for you: https://meetings.aps.org/Meeting/DPP21/Session/JP11.15 https://meetings.aps.org/Meeting/DPP21/Session/JP11.15 > Since cosmic rays are unaffected by the galaxy’s gravity, they increase the buoyancy of the ISM. However, the cosmic ray fluid has a finite compressibility, increasing the energy required to form valleys. Linear theory suggests this compressibility dominates buoyancy, suppressing the instability. > To address this counterintuitive result, we run local simulations of injections of cosmic ray pressure in the galactic disk. This assumes a supernova as the source. If this physically motivated perturbation creates buoyant magnetic flux tubes, then it is likely the Parker instability can develop in the ISM even if instability criteria from linear theory are not met. https://en.wikipedia.org/wiki/Nova#Recurrent_nova https://en.wikipedia.org/wiki/Nova#Recurrent_nova https://www.syfy.com/syfy-wire/bad-astronomy-a-micronova-is-a-new-kind-of-stellar-explosion https://www.syfy.com/syfy-wire/bad-astronomy-a-micronova-is-...

xattt 3y ago

I’m trying to understand what kind of phenomenon beams a column of light into the sky from the South Pole. I can understand auroral curtains, but a cylinder beam sounds far-fetched.

michaelsbradley 3y ago
Birkeland current

klondike_klive 3y ago

> Peratt interpreted dotted circles and concentric circles as bottom-up renditions of a diocotron instability affecting the hollow outer sheets of the z-pinch I love this sentence. I am pretty inarticulate in person, sometimes I fantasise myself delivering lines like this in a hastily erected mobile command centre. "In English, please, professor?" growls a FBI agent. My acolyte pushes their glasses up "uh... uh... if you consider these petroglyphs as a correlate of an instability in the solid inner core of the lower segment of the auroral-" the FBI agent pinches his temples and rounds on the eager young researcher, "You better start making sense, pencil-neck!" I step gently in between them "In simple terms, we're talking about... a Miyake Event."

ambicapter 3y ago
You're just a screenplay away from playing your dream self in a movie.
HerculePoirot 3y ago
Got some more for you: https://meetings.aps.org/Meeting/DPP21/Session/JP11.15 https://meetings.aps.org/Meeting/DPP21/Session/JP11.15 > Since cosmic rays are unaffected by the galaxy’s gravity, they increase the buoyancy of the ISM. However, the cosmic ray fluid has a finite compressibility, increasing the energy required to form valleys. Linear theory suggests this compressibility dominates buoyancy, suppressing the instability. > To address this counterintuitive result, we run local simulations of injections of cosmic ray pressure in the galactic disk. This assumes a supernova as the source. If this physically motivated perturbation creates buoyant magnetic flux tubes, then it is likely the Parker instability can develop in the ISM even if instability criteria from linear theory are not met. https://en.wikipedia.org/wiki/Nova#Recurrent_nova https://en.wikipedia.org/wiki/Nova#Recurrent_nova https://www.syfy.com/syfy-wire/bad-astronomy-a-micronova-is-a-new-kind-of-stellar-explosion https://www.syfy.com/syfy-wire/bad-astronomy-a-micronova-is-...