Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.
-
Upload
arnold-wilcox -
Category
Documents
-
view
231 -
download
0
Transcript of Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.
![Page 1: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/1.jpg)
Lightning Spectroscopy
Thomas Walker
Hugh Christian
Dave Sentman
![Page 2: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/2.jpg)
Spectral Information
• Phantom v710– 670k fps
• 5 Angstroms/pixel dispersion
• Natural and Triggered Lightning at ICLRT
![Page 3: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/3.jpg)
Spectrometer Design
![Page 4: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/4.jpg)
![Page 5: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/5.jpg)
Sample Spectra
![Page 6: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/6.jpg)
![Page 7: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/7.jpg)
![Page 8: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/8.jpg)
Channel Base Current (A) Wavelength (Å)
Cu
Hα
![Page 9: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/9.jpg)
TIM
E
![Page 10: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/10.jpg)
Videos
Triggered Lightning
Natural
![Page 11: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/11.jpg)
670,000 fps triggered return stroke
![Page 12: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/12.jpg)
670,000 fps natural return stroke
![Page 13: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/13.jpg)
Physical Properties
• Temperature– Ratios of Lines (M. Prueitt and R. Orville)
• Number Density– FWHM H-alpha– Ratio of Intensities of Singly Ionized lines to Neutral
Lines of the same species
• Luminosity– Integrating over the entire spectrum
• Confinement• Conductivity
![Page 14: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/14.jpg)
![Page 15: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/15.jpg)
![Page 16: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/16.jpg)
![Page 17: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/17.jpg)
![Page 18: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/18.jpg)
![Page 19: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/19.jpg)
![Page 20: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/20.jpg)
![Page 21: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/21.jpg)
![Page 22: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/22.jpg)
Magnetic Confinement
Hydrostatic Equilibrium
These equations in conjunction with Ideal Gas Law yields:
Ampere’s Law
![Page 23: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/23.jpg)
![Page 24: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/24.jpg)
Conductivity
Ohm’s Law Langevin Equation
Using these equations along with the collisional frequency it can be shown that the conductivity is:
Λ is a function of Temperature and weakly number density
![Page 25: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/25.jpg)
![Page 26: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/26.jpg)
High Speed Spectroscopy – what next?
• Continue to probe the lightning physics• time resolved full gas dynamical model• measure peak temperature, density and luminosity
• Using synthetic spectra, identify spectral anomalies
•
![Page 27: Lightning Spectroscopy Thomas Walker Hugh Christian Dave Sentman.](https://reader036.fdocuments.net/reader036/viewer/2022081421/56649e7b5503460f94b7b909/html5/thumbnails/27.jpg)
High Speed Spectroscopy – what next?
– Why is H alpha so strong– Is Local Thermal Dynamic Equilibrium always in play?– Does the axial electric filed affect electron energy and hence the spectra?
• Determine the physical characteristics of the leader including the electric field in front of the leader
• Determine the physical characteristics of intercloud lightning• How do the energetics compare?• what is the channel diameter, temperature and density?
• Measure the spectra of the cooling channel– identify molecular species as it cools – Nox
• Remotely detect inner shell processes– Auger emissions– May help determine when high energy electrons are being emitted inside the cloud
• Remotely estimate lightning currents as a function of time?– Use in conjunction with the HAMMA array to intercompare estimates– Calculate total lighting energetics– Implications for GLM