34th Solar Physics Division Meeting, June 2003 Propagating Disturbances in the Lower Solar Corona...
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Transcript of 34th Solar Physics Division Meeting, June 2003 Propagating Disturbances in the Lower Solar Corona...
![Page 1: 34th Solar Physics Division Meeting, June 2003 Propagating Disturbances in the Lower Solar Corona Meredith J. Wills-Davey Southwest Research Institute.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfb71a28abf838c9e987/html5/thumbnails/1.jpg)
34th Solar Physics Division Meeting, June 2003
Propagating Disturbances in the Lower Solar Corona
Meredith J. Wills-DaveySouthwest Research Institute
Boulder, [email protected]
![Page 2: 34th Solar Physics Division Meeting, June 2003 Propagating Disturbances in the Lower Solar Corona Meredith J. Wills-Davey Southwest Research Institute.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfb71a28abf838c9e987/html5/thumbnails/2.jpg)
34th Solar Physics Division Meeting, June 2003
Summary
Analysis of TRACE 13 June 1998 event
Wave profiles, flux
Evidence for spatial constraints on propagation?Implications of spatial constraints (“wave guides”)Conclusions
![Page 3: 34th Solar Physics Division Meeting, June 2003 Propagating Disturbances in the Lower Solar Corona Meredith J. Wills-Davey Southwest Research Institute.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfb71a28abf838c9e987/html5/thumbnails/3.jpg)
34th Solar Physics Division Meeting, June 2003
Wave fronts, trajectories can be automatically tracked, are complex
Thick black lines: measured wavefront positions at successive times
Thin black lines: interpolated wavefront positions
Thin white lines: natural propagation tracks between interpolated fronts
Thick white lines: tracks chosen for analysis
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34th Solar Physics Division Meeting, June 2003
Cross-sections of density enhancement along tracks show
propagation
Time Density Enhanceme
nt
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34th Solar Physics Division Meeting, June 2003
Wave kinetic energy flux does not match expectations for an impulsive
driver
Time
Total wave kinetic energy flux
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34th Solar Physics Division Meeting, June 2003
Comparison of TRACE passbands suggests minimum altitude
![Page 7: 34th Solar Physics Division Meeting, June 2003 Propagating Disturbances in the Lower Solar Corona Meredith J. Wills-Davey Southwest Research Institute.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfb71a28abf838c9e987/html5/thumbnails/7.jpg)
34th Solar Physics Division Meeting, June 2003
Is there a maximum altitude? Evidence in theories and simulations
Original theoriesUchida (1968)Meyer (1968)
Meyer increasing Alfvén speed with altitude creates wave guidewave guideUchida shallower trajectories trapped in the atmosphere Uchida (1968)
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34th Solar Physics Division Meeting, June 2003
Our simple model
Turnover in a stratified atmosphere
Terradas, Oliver, & Ballester (1999) finds trapping, analogous to turnover predicted by Meyer
Is there a maximum altitude? Evidence in theories and simulations
![Page 9: 34th Solar Physics Division Meeting, June 2003 Propagating Disturbances in the Lower Solar Corona Meredith J. Wills-Davey Southwest Research Institute.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfb71a28abf838c9e987/html5/thumbnails/9.jpg)
34th Solar Physics Division Meeting, June 2003
“Wave guiding” is consistent with current observations
EIT WavesUniformity of observationsDiscrepancy between propagating wave observations in EUV and soft x-ray corona
Courtesy of B. Thompson
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34th Solar Physics Division Meeting, June 2003
ConclusionsPropagations are complex, reflecting complexity of the medium
Coronal Seismology?
Wave driver is non-impulsive, delivering energy over a period of minutes
CME as driver?
Propagations not consistent with spherical expansion, appear to be trapped in a coronal “wave guide”
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34th Solar Physics Division Meeting, June 2003
A Surprising Find
Dispersion of the wave should relate to change in pulse width
No measurable width increaseResults consist with Results consist with dispersionless dispersionless conditionsconditions
Time
Pulse width