Lucas Tarr PhD! RECENT [2020+] EMAIL: ltarr@nso.edu

Lucas Tarr Department of Physics Montana State University Bozeman, MT 59717-3840 Advisor: Dr. Dana Longcope

Curriculum Vitae

Research Interests

• Magnetic topology of the solar photosphere and corona
• Heating of coronal plasma
• Coronal response to emerging flux
• Using analysis of the above to figure out what happens to coronal plasma

Current and recent projects

I use the Minimum Current Corona (MCC) to model the evolution of photospheric magnetic fields, which are themselves modeled at each time as a Magnetic Charge Topology (MCT). My major contribution has been to allow for regions with variable amounts of flux, the point of which is to study regions with emerging and/or "submerging" flux. I use quotes for the latter, while active-region scale emergence does seem to fit the cartoon of a large, inverted-U-shaped fluxtube crossing photospheric boundary, active-region scale submergence often does not. Instead, each concentrated footpoint appears to separately diffuse and break up into smaller, lower strength chunks by reconnection with the surrounding quiet Sun field.
I have currently applied this framework to a couple regions:

AR11112:

Here's an HMI magnetogram movie of NOAA Active Region 11112, which had a GOES M3.0 flare on October 16th, 2010.

And here's the same region, only now looking at 171 Angstrom data from AIA, rather than a magnetogram from HMI. Just for perspective, the tick marks in those movies are each about the size of Earth. These systems are big!

Test of java script movie of the same thing.

AR11158:
My recent work is a case study focusing on NOAA AR 11158.

List of observed supposed magnetic null points:
See here.

Publications

• Quiescent Reconnection Rate Between Emerging Active Regions and Preexisting Field, with Associated Heating: NOAA AR 11112, Tarr, Longcope, McKenzie, and Yoshimura, 2014, SolPhys, 289, 3331-3349.
• Energetic Consequences of Flux Emergence, Tarr, 2013 PhD, Montana State University
• Calculating Separate Magnetic Free Energy Estimates for Active Regions Producing Multiple Flares: NOAA AR11158, Tarr, Longcope, and Millhouse, 2013, ApJ, 770, 4 ( ADS)
• Outflows And Dark Bands At Arcade-Like Active Region Core Boundaries, Scott, Martens, and Tarr, 2013, ApJ, 765, 82 (ADS)
• The Role of Fast Magnetosonic Waves in the Release and Conversion via Reconnection of Energy Stored by a Current Sheet, Longcope and Tarr, 2012, ApJ, 756, 192 (ADS)
• Calculating energy storage due to topological changes in emerging active region NOAA AR 11112 , Tarr and Longcope, 2012, ApJ, 749, 64 (ADS)
• Understanding the differences in 3 consecutive large flares, Tarr and Longcope, 2012, ASPCS - Hinode 5 (ADS)
• Undergraduate thesis, Tarr, 2005, Reed College, Portland, OR

Talks and Posters

• SPD2014 Science Meeting: June, 2014, Boston, MA - Spectropolarimetic observations and inversions of a small active region with IBIS
• SPD2013 Science Meeting: July, 2013, Bozeman, MT - Observations of quiescent reconnection; Dissertation Talk
• Flare Prediction Breakout, LWS/SDO Science Meeting: March, 2013, Cambridge, MD - Using MCT/MCC for flare prediction. [invited!]
• Relativity and Astrophysics Seminar, MSU: January, 2013, Bozeman, MT - modified version of Stanford talk.
• Stanford Solar Seminar: October, 2012, Palo Alto, CA
• Hinode 6: August, 2012, St. Andrews, Scotland, UK
• SPD 2012: June, 2012, Anchorage, AK
• Hinode 5: October, 2011, Cambridge, MA
• SPD 2011: June, 2011, Las Cruces, NM - Slightly condensed version of LWS/SDO-I talk.
• LWS/SDO-I: May, 2011, Squaw Creek, CA
• SPD 2010: June, 2010, Miami, FL
• SPD 2009: June, 2009, Boulder, CO

REU 2011 IDL Notes

Background and other things

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• 2: On the internet, for every caricature, there is an equal and opposite caricature. Troll at your own risk.

Last Updated: May, 2013