I’m a research scientist at Southwest Research Institute in Boulder, Colorado. I recently finished my PhD with Steven Cranmer at the University of Colorado, Boulder, where I studied the motion of magnetic bright points on the solar photosphere as drivers of coronal heating via Alfvén waves. In the past, I’ve worked on thermophysical modeling of Martian sand dunes and on refining estimates of collisional timescales of asteroids.

Here’s what I’ve recently worked on, described for a…

Solar Physicist: I’m studying photospheric bright points, the bases of flux tubes that rise to the corona. Following the motion of these bright points reveals how the flux tubes are being shaken by convective churning, and this shaking is believed to excite waves in the flux tubes which carry energy to the corona. These bright points have been unresolved blobs until now, but DKIST will start to resolve them. I’m using simulated observations of DKIST-like resolution and cadence from MHD simulations to prepare and validate analysis techniques for resolved bright-point motion that can overcome the problems of traditional centroid-tracking applied to resolved motion while also taking advantage of the additional information available in resolved images—specifically, the evolution of the shape and size of bright points, which should excite wave modes beyond those driven by bulk, centroid motion.

Normal Person: The surface of the Sun is about 10,000°F (6000°C), but there’s a sort of atmosphere around the Sun, called the corona, which is a million degrees. One of the big questions in solar physics is how the corona can be heated to a million degrees by the relatively-cool solar surface—it’s like boiling a pot of water without turning on the stove. One possible explanation involes what we call flux tubes, which are tubes of gas held together magnetically. These tubes are all over on the Sun. They have one end inside the Sun’s upper layers and the other end is up inside the corona. The bottoms of these tubes get shaken by the churning, boiling motion of the Sun’s surface. This makes the whole tube above the surface shake back and forth, which means waves are traveling up the tubes. When these waves get up into the corona, they shake around the gas, heating it up. This is where we think the corona’s temperature comes from, magnetic waves injecting heat directly into the corona. It’s like boiling water with a microwave oven instead of a stove top—the water’s boiled by microwaves injecting heat directly into the water, instead of by putting the water in contact with a hot stovetop. My research, then, is looking at just how the bases of those tubes are shaken around. I’m using computer simulations of the Sun, because I can look more closely and in more detail than can be done with telescopes. I’m preparing analysis techniques to study the motion of these tube bases as will be seen by DKIST, an upcoming solar telescope that will produce clearer images of the solar surface than have ever been made before.

Five-Year-Old: The Sun is like a big ball of fire in space, and it’s super hot. But there’s a little bit of air in between the Sun and space, and it’s super mega ultra hot! We want to know why the Sun makes that air super mega ultra hot instead of just making it super hot like itself. We think it’s because the Sun works kind of like a microwave when it heats up that air, but we’re not quite sure yet. We’re working on it! I’m using special computer tools to look really closely at the surface of the Sun to see how this all works.

Recent Work

PhD Dissertation
I’m not saying you should read the whole thing, but here it is.
“A Refined Model of Convectively Driven Flicker in Kepler Light Curves”
A paper on work I’ve done looking at the observational signal of stellar granulation, seen in low-amplitude, short-timescale variations in the star’s brightness. I’ve improved the ability of a physical model to predict this signal’s amplitude and pointed to where additional simulation work can further improve this model (or where the observations might provide constraints for those simulations). [arXiv, ADS, ApJ]
SHINE 2019 poster thumbnail
“Coronal Turbulence Driven from the Photosphere: Opportunities for DKIST”
My poster for SHINE 2019, describing past work and future plans and progress. An updated version of the SPD poster below.
“Preparing for DKIST: Connecting the High-Resolution Sun to the Turbulent Corona”
My poster for SPD/AAS 2019, describing past work and future plans and progress. [ADS]
“Investigating the Complex Motions of Photospheric Bright Points as a Lower Boundary Condition for Coronal Magnetism”
My AGU 2018 poster summarizing previous work and describing future plans. Abstract
Paper on Bright Point Tracking
My first paper! It’s on the same topic as the bright point poster listed next, but goes into more depth and includes an appendix discussing the difficulty of solidly defining how a bright point moves. [arXivADSApJ]
“Characterizing the Motion of Photospheric Bright Points at High Resolution”
I’m currently using simulations to characterize at high resolution the motion of magnetic bright points in the inter-granular lanes of the solar photosphere. These bright points are regions of strong, vertical magnetic flux, and they are buffeted about by the convective churning of the plasma. Their back-and-forth motion creates Alfvén waves in the magnetic field lines, carrying energy into the upper corona where it’s deposited as heat. [ADS]
“Investigating the Poleward Trend of Southern Dune Field Stabilization on Mars Using Thermophysical Observations”
I spent a year looking for evidence of water ice underneath Martian sand dunes that might be cementing the dunes in place. This poster was Abstract 2528 at LPSC 2016, and an earlier version was Abstract 8052 at the Fourth International Planetary Dunes Workshop.
“Refining Asteroid Collision Timescales”
Concluding my undergraduate research, I produced refined estimates of the timescales for asteroid collisions. This work was presented as a talk at the 2013 meeting of the Michigan Space Grant Consortium.
“Family Membership of Koronis Zone Asteroids”
We presented effective techniques and results for investigating asteroid families through multiple, disjoint data catalogs. This work was presented as a talk at the 2012 meeting of the Michigan Space Grant Consortium.
“Asteroid Collisions”
Marking my first undergraduate research project, I present progress and future plans regarding probabilities of collisions between asteroids. This poster was presented at the 2011 meeting of the Michigan Space Grant Consortium.
Sometimes maintaining a CV feels like a whole project in itself.

Non-Research Projects

Astronomy Publication Proximity Analyzer
APPA uses the ADS database to let you explore connections between authors. Type in two names and APPA will find the chains of coauthorship (person A published a paper with B, who wrote a paper with C…) connecting those two names.
Finn Stickers App
Gboard on Android lets you send stickers from the keyboard, and while it includes its own set of stickers, any app on the phone can provide more stickers through the keyboard. I made myself an app to do just that! It currently features two sticker packs, one featuring my friends’ dog Finn (the world’s best!), and another featuring my world-traveling cow puppet, Cowwy. Friends and family have given it a 5-star rating!
Finn Stickers on the Google Assistant
Those same stickers available in my Android app are also available through the Google Assistant. On any phone with the Assistant, say “OK Google, talk to Finn Stickers” to see Finn and Cowwy pictures on demand, no installation required!
Calvin Webcam Timelapse
I recorded a year’s worth of images from the pubic webcams surveying my undergrad campus and had some fun making composite images and timelapses.

Personal & Contact Info

Southwest Research Institute
1050 Walnut St. Suite 300
Boulder, CO 80302
United States

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