University:
Boston University
Course:
CAS PY 106 | Physics 2
Academic year:

2019
Views:

278

Pages:

10
Author:

Clint W.

Auroral Ionospheric Plasma Processes Questions about auroral drivers Questions about ionospheric response “…no technology barriers that would prevent making temperature and wind measurements of the neutral atmosphere well into the thermosphere to 1000 km. This capability would open an entirely new region of chemistry and atmospheric modeling..." •! Auroral-driven ionospherethermosphere responses •! Ion fountain, sawtooth events, neutral upwelling, charge exchange, Alfvenic feedback, ion outflow…. •! Here: consider details of responses to auroral drivers Image by Tom Moore, GSFC “Scifer Cleft ion fountain” Questions about ionospheric feedbacks •! Streltsov/Lotko Ionospheric Alfven Resonator •! Filamentation of downward current region •! Predicts strong distortion of ionospheric footpoint ! Figure 1. Modeled response of the ionosphere to the ionospheric feedback instability producing structured FAC in the downward-current region. Questions about ionospheric structuring and dynamics •! Zettergren and Semeter, 2012 •! Effects of composition and collisions •! 2D electrostatic Introduction: Questions •! How to make an in situ map of auroral ionosphere? •! How to monitor response of a thermal plasma to drivers? •! Challenged assumptions: –! !sheath >> kTe –! time and space variations –! flows Introduction: Goals •! Auroral zone: lower altitudes, lower energy coupling •! Conductivity gradients: source of current •! Shears and density gradients: wave growth •! Response of thermal ambient plasma: –! Sheaths, charging, wakes, flows •! Multipoint array of sensorcraft: –! Building a time-space map of ionospheric density evolution and structure Outline •! •! •! •! •! •! Aurora Ionosphere Plasma Processes Instrumentation and measurements Swarms Jan Curtis! Outline •! Aurora –! –! –! –! –! –! •! •! •! •! •! Morphology E and J Upward/downward/Alfvenic Visible and f(v) types Driver Feedback Ionosphere Plasma Processes Instrumentation and measurements Swarms Jan Curtis!

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