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Stephen Bradshaw
Assistant Professor
William V. Vietti Junior Chair of Space Physics
 
e-mail:Stephen.Bradshaw@rice.edu
 
  • Ph.D. Solar astrophysics (2004) Cambridge University, Cambridge, England, UK
  • M.Phys. (1st class honours) Physics with Planetary and Space Physics (2000) Aberystwyth University, Aberystwyth, Wales, UK
 
Primary Department
   Department of Physics and Astronomy
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Department Affiliations
 
  • Department of Physics and Astronomy
  •  
    Websites
     Rice University Solar Physics Group
     
    Research Areas
     1. Astrophysics of the Sun: heating in the solar atmosphere; flares; heating and acceleration of the slow solar wind; energy transport processes; time-dependent ionization states; emission line spectroscopy. 2. Plasma physics: electron and ion kinetics; non-equilibrium processes; non-local phenomena; hybrid fluid-kinetic approaches. 3. Numerical modeling: high-order solvers; shock capturing; adaptive grids.
     
    Plasma physics
     

    I am particularly interested in phenomena that arise in high temperature and low density plasma, where the constituent particles can become effectively collisionless. A non-Maxwellian distribution can be induced when electrons stream collisionlessly from regions of hot, tenuous plasma (such as the solar corona) into cool, dense plasma (such as the solar chromosphere) whereupon they modify the local electron distribution, by adding a high-energy population to its tail, and drive it away from thermal equilibrium. Thermal conduction can be enhanced by a significant population of energetic tail electrons and so can the collisional ionisation rate, which in turn alters the ionisation state of the plasma and the properties of its emission spectrum. This is particularly important because everything we know about the Sun has been derived from, or confirmed by, its emission spectrum. The decoupling of thermal conduction and the ionisation state from the local thermal properties of the plasma is a phenomena called non-localisation.


    I have developed a kinetic component for my computational fluid-based model to allow the study of non-Maxwellian electron distributions and their importance to the physics of the solar atmosphere.

     
    Astrophysics of the Sun
     

    The focus of my research is on developing an understanding of heating in the solar corona and in the coronae of Sun-like stars. Coronal temperatures can reach several million degrees and yet surface temperatures are only a few thousand degrees. The mechanism by which such tremendous temperatures are achieved and maintained remains poorly understood. Indeed, it is one of the great, unsolved mysteries of astrophysics to this day.


    One possible mechanism for coronal heating is the small scale, rapid release of energy due to magnetic reconnection – so called nanoflares. Though a promising candidate, they have proven extremely difficult to detect and there is little observational evidence to verify their existence. Theoretical attempts to understand the consequences of this form of heating and to predict more likely observational signatures have been limited. Modeling studies have neglected certain key aspects of coronal plasma physics; in particular, the time-dependence of the ionisation state and the formation of strongly non-Maxwellian electron distributions.


    I have carried out work to address these limitations by developing a new and unique computational model which for the first time accounts for both of these processes. Traditional numerical approaches to the coronal heating problem assume an ionisation balance in equilibrium with the plasma, near-Maxwellian electron distributions and a single temperature for all particle species. The new model dispenses with these assumptions and provides a far more realistic physical treatment of coronal plasma.

     
    Numerical modeling
     

    The computational model that I have developed is based upon the numerical solution of the hydrodynamic equations for multi-species plasma. These are a coupled system of strongly non-linear partial differential equations comprising hyperbolic, parabolic and ordinary source terms which describe a multitude of physical processes: convection; thermal conduction; wave phenomena; shocks; viscous effects; collisions; heating; and optically-thin radiation. Solving these equations requires the implementation of advanced numerical techniques.


    In addition, the equations which describe the evolution of the ionisation state, and are coupled to the hydrodynamic equations via the radiation term, are numerically stiff. I have developed novel methods to solve these equations in order that otherwise intractable problems can be handled within reasonable time-frames and using relatively modest computational resources.


    The spatial-scales that are important in solar and stellar atmospheres present further challenges. Scale lengths range from several hundred kilometres to just a few metres. It is usually not feasible to employ high resolution everywhere in a numerical solution and so resolving small scale features (while not over-resolving large scale features) requires the use of adaptive computational grids. I have designed and implemented a number of sophisticated adaptive grid strategies including: low-order reconstruction for discontinuities (e.g. shocks) and associated tracking methods; and high-order reconstruction for smooth regions of the solution.

     
    Teaching Areas
     Solar astrophysics; plasma physics; stars, galaxies, and the universe; exploration of the solar system.
     
    Selected Publications
     Refereed articles
     

    Barnes, W.T., Cargill, P.J., & Bradshaw, S.J., 2016, Inference of Heating Properties from "Hot" Non-flaring Plasmas in Active Region Cores I. Single Nanoflares, Astrophysical Journal, 833, 217

     
     

    Barnes, W.T., Cargill, P.J., & Bradshaw, S.J., 2016, Inference of Heating Properties from "Hot" Non-flaring Plasmas in Active Region Cores II. Nanoflare Trains, Astrophysical Journal, 829, 31

     
     

    Bradshaw, S.J., & Viall, N.M., 2016, Signatures of activity in a global model of a solar active region, Astrophysical Journal, 821, 63

     
     

    Reep, J.W., Bradshaw, S.J., & Holman, G.D., 2016, X-ray source heights in a solar flare: thick-target versus thermal conduction front heating, Astrophysical Journal, 818, 44

     
     

    Bradshaw, S.J., & Klimchuk, J.A., 2015, Chromospheric nanoflares as a source of coronal plasma: II. Repeating nanoflares, Astrophysical Journal, 811, 129

     
     

    Cargill, P.J., Warren, H.P., & Bradshaw, S.J., 2015, Modelling nanoflares in active regions and implications for coronal heating mechanisms, Philosophical Transactions of the Royal Society A, 373: 20140260

     
     

    McQuillen, P., Castro, J., Bradshaw, S.J., & Killian, T.C., 2015, Emergence of kinetic behavior in streaming ultracold neutral plasmas, Physics of Plasmas, 22, 043514

     
     

    Price, D.J., Taroyan, Y., Innes, D.E., & Bradshaw, S.J., 2015, Forward modeling of a brightening observed by AIA, Solar Physics, 290, 1931

     
     

    Reep, J.W., Bradshaw, S.J., & Alexander, D.A., 2015, Optimal electron energy ranges for driving chromospheric evaporation in solar flares, Astrophysical Journal, 808, 177

     
     

    Bradshaw, S.J., & Hartigan, P., 2014, On the lifetimes of sunspots and starspots, Astrophysical Journal, 795, 79

     
     

    Klimchuk, J. A., & Bradshaw, S.J., 2014, Are chromospheric nanoflares a primary source of coronal plasma?, Astrophysical Journal, 791, 60

     
     

    Taroyan, Y., & Bradshaw, S.J., 2014, Forward modeling of Doppler shifts in EUV spectral lines, Solar Physics, 289, 1959

     
     

    Bradshaw, S.J., & Cargill, P.J., 2013, The influence of numerical resolution on coronal density in hydrodynamic models of impulsive heating, Astrophysical Journal, 770, 12

     
     

    Bradshaw, S.J., & Raymond, J., 2013, Collisional and radiative processes in optically-thin plasmas, Space Science Reviews, 24

     
     

    Cargill, P.J., & Bradshaw, S.J. 2013, The cooling of coronal plasmas. IV. Catastrophic cooling of loops, Astrophysical Journal, 772, 40

     
     

    McQuillen, P., Castro, J., Strickler, T., Bradshaw, S.J., & Killian, T.C., 2013, Ion holes in ultracold neutral plasmas, Physics of Plasmas, 20, 043516

     
     

    Reep, J.W., Bradshaw, S.J., & Klimchuk, J.A. 2013, Diagnosing the time-dependence of active region core heating from the emission measure. II. Nanoflare trains, Astrophysical Journal, 764, 193

     
     

    Reep, J.W., Bradshaw, S.J., & McAteer, R.T.J. 2013, On the sensitivity of the GOES flare classification to properties of the electron beam in the thick target model, Astrophysical Journal, 778, 76

     
     

    Bradshaw, S.J., Klimchuk, J.A., & Reep, J.W., 2012, Diagnosing the time-dependence of active region core heating from the emission measure: I. Low-frequency nanoflares, Astrophysical Journal, 758, 53

     
     

    Cargill, P.J., Bradshaw, S.J., & Klimchuk, J.A., 2012, Enthalpy-based thermal evolution of loops: II. Improvements to the model, Astrophysical Journal, 752, 161

     
     

    Cargill, P.J., Bradshaw, S.J., & Klimchuk, J.A., 2012, Enthalpy-based thermal evolution of loops: III. Comparison of models, Astrophysical Journal, 758, 5

     
     

    Petkaki, P., Del Zanna, G., Mason, H.E., & Bradshaw, S.J., 2012, SDO AIA and EVE observations and modeling of solar flare loops, Astronomy & Astrophysics, 547, 25

     
     

    Tripathi, D., Mason, H.E., Del Zanna, G., & Bradshaw, S.J., 2012, Observations of plasma upflow in a warm loop with Hinode/EIS, Astrophysical Journal, 754, L4

     
     

    Bradshaw, S.J., & Klimchuk, J.A., 2011, What dominates the coronal emission spectrum during the cycle of heating and cooling?, Astrophysical Journal Supplement Series, 194, 26

     
     

    Bradshaw, S.J., Aulanier, G., & Del Zanna, G., 2011, A reconnection-driven rarefaction wave model for coronal outflows, Astrophysical Journal, 743, 66

     
     

    Del Zanna, G., Mitra-Kraev, U., Bradshaw, S.J., Mason, H.E., & Asahi, A., 2011, The 22 May 2007 B-class flare: new insights from Hinode observations, Astronomy & Astrophysics, 526, 1

     
     

    Taroyan, Y., Erdelyi, R., & Bradshaw, S.J., 2011, Forward modeling of coronal loops: impulsive heating with a power law distribution of energies, Solar Physics, 269, 295

     
     

    Bradshaw, S.J., & Cargill, P.J., 2010, A new enthalpy-based approach to the transition region in an impulsively-heated corona, Astrophysical Journal Letters, 710, 39

     
     

    Bradshaw, S.J., & Cargill, P.J., 2010, The cooling of coronal plasmas: III. The importance of enthalpy as a mechanism for energy loss, Astrophysical Journal, 717, 163

     
     

    Longcope, D.W., & Bradshaw, S.J., 2010, Slow Shocks and Conduction Fronts from Petschek Reconnection of Skewed Magnetic Fields: Two-fluid Effects, Astrophysical Journal, 718, 149

     
     

    Bradshaw, S.J., 2009, A numerical tool for the calculation of non-equilibrium ionisation states in the solar corona and other astrophysical plasma environments, Astronomy & Astrophysics Supplement Series, 502, 409

     
     

    Bradshaw, S.J., 2008, A reinterpretation of the energy balance in active region loops following new results from Hinode EIS, Astronomy & Astrophysics Letters, 406, 5

     
     

    Bradshaw, S.J., & Erdelyi, R., 2008, Radiative damping of standing acoustic waves in solar coronal loops, Astronomy & Astrophysics, 483, 301

     
     

    De Moortel, I., & Bradshaw, S.J., 2008, Forward modeling of coronal intensity perturbations, Solar Physics, 252, 101

     
     

    Taroyan, Y., & Bradshaw, S.J., 2008, Coronal loop oscillations and diagnostics with Hinode/EIS, Astronomy & Astrophysics, 481, 247

     
     

    West, M.J., Bradshaw, S.J., & Cargill, P.J., 2008, On the lifetime of hot coronal plasmas arising from nanoflares, Solar Physics, 252, 89

     
     

    Buchlin, E., Cargill, P.J., Bradshaw, S.J., & Velli, M., 2007, Profiles of heating in turbulent coronal magnetic loops, Astronomy & Astrophysics, 469, 347

     
     

    Taroyan, Y., Erdelyi, R., Doyle, J.G., & Bradshaw, S.J., 2007, Analysis of power spectra of Doppler shift time series as a diagnostic tool for quiescent coronal loops, Astronomy & Astrophysics, 462, 331

     
     

    Taroyan, Y.; Erdélyi, R.; Wang, T. J.; Bradshaw, S.J., 2007, Forward modelling of hot loop oscillations observed by SUMER and SXT, Astrophysical Journal Letters, 659, 173

     
     

    Bradshaw, S.J., & Cargill, P.J., 2006, Explosive heating of low-density coronal plasma, Astronomy & Astrophysics, 458, 987

     
     

    Del Zanna, G., Schmieder, B., Mason, H.E., Berlicki, A., Bradshaw, S.J., 2006, The gradual phase of the X17 flare on October 28, 2003, Solar Physics, 239, 173

     
     

    Doyle, J.G., Taroyan, Y., Ishak, B., Madjarska, M.S., & Bradshaw, S.J., 2006, Study of a transient siphon flow in a cold loop, Astronomy & Astrophysics, 452, 1075

     
     

    Taroyan, Y., Bradshaw, S.J., & Doyle, J.G., 2006, Nanoflare heating of coronal loops: hydrodynamic response and observational consequences, Astronomy & Astrophysics, 446, 315

     
     

    Bradshaw, S.J., & Cargill, P.J., 2005, The cooling of coronal plasmas: II. Properties of the radiative phase, Astronomy & Astrophysics, 437, 311

     
     

    Taroyan, Y., Erdelyi, R., Doyle, J.G., & Bradshaw, S.J., 2005, Footpoint excitation of standing acoustic waves in coronal loops, Astronomy & Astrophysics, 438, 713

     
     

    Bradshaw, S.J., Del Zanna, G., & Mason, H.E., 2004, On the consequences of a non-equilibrium ionisation balance for compact flare emission and dynamics, Astronomy & Astrophysics, 425, 287

     
     

    Bradshaw, S.J., & Mason, H.E., 2003, A self-consistent treatment of radiation in coronal loop modeling, Astronomy & Astrophysics, 401, 699

     
     

    Bradshaw, S.J., & Mason, H.E., 2003, The radiative response of solar loop plasma to transient heating, Astronomy & Astrophysics, 407, 1127

     
     Articles
     

    Bradshaw, S.J., 2012, Solar Physics: Swirls in the corona, Nature, 486, 476

     
     

    De Moortel, I., Browning, P., Bradshaw, S.J., Pintér, B., Kontar, E.P., 2008, The way forward for coronal heating, Astronomy & Geophysics, 49, 21

     
     Book chapters
     

    Bradshaw, S.J., & Raymond, J., 2014, Collisional and radiative processes in optically thin plasmas, in Microphysics of Cosmic Plasmas, Space Sciences Series of ISSI Volume 47, pp 195-230

     
     Conference papers
     

    Del Zanna, G., Mitra-Kraev, U., Bradshaw, S.J., Mason, H.E., & Asai, A., 2011, Hinode observations and modeling of small flares, Astronomical Society of the Pacific Conference Series, 455, 295

     
     

    Buchlin, E., Bradshaw, S.J., Cargill, P.J., Velli, M., 2010, Turbulent heating and cooling of coronal loops, Proceedings of the 38th COSPAR Scientific Assembly, 38, 2834

     
     

    Del Zanna, G., & Bradshaw, S.J., 2009, Coronal loops: new insights from EIS observations, Astronomical Society of the Pacific Conference Series, 415, 264

     
     

    Buchlin, E., Cargill, P.J., Bradshaw, S.J., & Velli, M., 2008, Spectroscopic Hinode observables from turbulent heating and cooling of coronal loops, Astronomical Society of the Pacific Conference Series, 397, 83

     
     

    Taroyan, Y., Doyle, J.G., Ishak, B., Madjarska, M.S., & Bradshaw, S.J., 2005, Study of a transient siphon flow in a cold loop, Proceedings of The Dynamic Sun: Challenges for Theory and Observations, ESA SP-600, 25

     
     

    Bradshaw, S.J., Del Zanna, G., Mason, H.E., & Cargill, P.J., 2004, Synthesised radiative emission from a nanoflare heated elemental solar loop, Proceedings of SOHO 15 - Coronal Heating, ESA SP-575, 539

     
     

    Mason, H.E., Del Zanna, G., & Bradshaw, S.J., 2004, Remote sensing of plasma diagnostics relating to coronal heating, Proceedings of SOHO 15 – Coronal Heating, ESA SP-575, 312

     
     

    West, M.J., Cargill, P.J., & Bradshaw, S.J., 2004, Non-local heat conduction and its effect on coronal cooling times, Proceedings of SOHO 15 – Coronal Heating, ESA SP-575, 573

     
     Other
     

    Laming, J.M., et al., 2010, Science objectives for an X-ray microcalorimeter observing the Sun, A white paper submitted to the Solar and Heliophysics Decadal Survey, arXiv eprint: 1011.4052

     
    Presentations
     Conference Committee Member
     

    "Solar Coronal Loops Workshop VII." Cambridge, UK. (July 2015)

     
     

    "Coronal heating - using observables (flows and emission measure) to settle the question of steady vs. impulsive heating." International Space Science Institute (ISSI), Bern, Switzerland. (March 2014)

     
     

    "Solar Physics Division of the American Astronomical Society Meeting." Boston, MA. (June 2014).

     
     

    "Coronal heating - using observables (flows and emission measure) to settle the question of steady vs. impulsive heating." International Space Science Institute (ISSI), Bern, Switzerland. (March 2013)

     
     

    "Coronal heating - using observables (flows and emission measure) to settle the question of steady vs. impulsive heating." International Space Science Institute (ISSI), Bern, Switzerland. (February 2012)

     
     

    "Fifth Coronal Loops Workshop." Mallorca, Spain (July 2011).

     
     

    "Solar Physics Division of the American Astronomical Society Meeting." Las Cruces, NM. (June 2011).

     
     Conference Paper
     

    "Optimal Electron Energies for Driving Chromospheric Evaporation in Solar Flares.." UK Solar Physics Meeting, Nottingham, UK. (July 2016)

     
     

    "Patterns of Activity Revealed by a Time Lag Analysis of a Model Active Region.." Solar Physics Division of the American Astronomical Society Meeting, Boulder, CO. (June 2016)

     
     

    "Patterns of Activity Revealed by a Time Lag Analysis of a Model Active Region.." UK Solar Physics Meeting, Nottingham, UK. (July 2016)

     
     

    "Pinning down coronal heating properties in the presence of non-equilibrium ionization." IRIS 4 Workshop, Boulder, CO. (May 2015)

     
     

    "Pinning down coronal heating properties in the presence of non-equilibrium ionization." Triennial Earth-Sun Summit (TESS), Indianapolis, IN. (April 2015)

     
     

    "Revisiting explosive evaporation: what does the cut-off have to do with it?." RHESSI 14 Workshop, New Jersey, NJ. (August 2015)

     
     

    "Radiative signatures of the coronal heating and cooling cycle." Fifth Coronal Loops Workshop, Mallorca, Spain. (July 2011)

     
     

    "Radiative signatures of the coronal heating and cooling cycle." Solar Physics Division of the American Astronomical Society Meeting, Las Cruces, NM. (June 2011)

     
     

    "Energy transfer by enthalpy in the solar atmosphere." Solar Physics Division of the American Astronomical Society Meeting, Miami, FL. (May 2010)

     
     

    "HYDRAD and a fluid kinetic approach to numerical modeling of the solar corona." Solar Physics Division of the American Astronomical Society Meeting, Boulder, CO. (June 2009)

     
     

    "HYDRAD and a fluid kinetic approach to numerical modeling of the solar corona." Fourth Coronal Loops Workshop, Florence, Italy. (June 2009)

     
     

    "Hybrid fluid-kinetic models of the solar atmosphere." U.K. Solar Physics Meeting, Aberystwyth, U.K. (April 2006)

     
     

    "HYDRAD: A hydrodynamics code for time-dependent ionisation and forward modelling of EUV emission from the solar atmosphere." American Geophysical Union, New Orleans, LA. (May 2005)

     
     

    "Non-equilibrium ion populations and the consequences for observable quantities." U.K. Solar Physics Meeting, Edinburgh, U.K. (April 2004)

     
     

    "Radiative emission from transiently heated solar loops." Second Coronal Loops Workshop, Palermo, Sicily. (September 2004)

     
     

    "Synthesised radiative emission from a nanoflare heated elemental solar loop." SoHO 15: Coronal Heating, St. Andrews, U.K. (September 2004)

     
     

    "Non-equilibrium ion populations and consequences for radiative emission from impulsively heated loops." U.K. Solar Physics Meeting, Dublin, Ireland. (April 2003)

     
     

    "A comparison between theoretical and spectroscopic active region loop profiles." U.K. Solar Physics Meeting, Sheffield, U.K. (April 2002)

     
     

    "Accounting for the influence of non-equilibrium ion populations in hydrodynamic models of solar loops." First Coronal Loops Workshop, Orsay, France. (November 2002)

     
     

    "Self-consistent hydrodynamic models of solar loops." PPARC Advanced Summer School, Preston, U.K. (April 2002)

     
     

    "Hydrodynamic models of solar loops." PPARC Advanced Summer School, St. Andrews, U.K. (September 2001)

     
     Invited Talks
     

    "Modeling the Eruptive Lower Solar Atmosphere.." Exploring the Geospace Frontier: New Directions (Quo Vadis), Boulder, CO. (May 2016)

     
     

    "Solar Flares: Explosive Plasma Physics.." American Physical Society (Texas Section), Beaumont, TX. (April 2016)

     
     

    "Bridging plasma-based models of active region heating and the large-scale magnetic field." New Approaches in Coronal Heating, The Royal Society at Chicheley Hall (August 2014).

     
     

    Invited Speaker.  "The Sun at maximum,." Johnson Space Center Astronomical Society, Houston, TX. (April 2013)

     
     

    "The physical consequences of under-resolution for N-dimensional models of the solar atmosphere,." AAS / SPD 2013, Bozeman, MN. (July 2013)

     
     

    "Heating requirements for the solar corona (and some alternatives to wave heating)." BUKS 2012, Crete, Greece. (July 2012)

     
     

    "Ionization and Radiative Processes." Microphysics of Cosmic Plasmas, International Space Science Institute (ISSI), Bern, Switzerland. (April 2012)

     
     

    "The Sun and Space Weather." Houston Astronomical Society Meeting, University of Houston, TX. (March 2011)

     
     

    "Non-equilibrium processes in the solar corona." Solar Plasma Spectroscopy: Achievements and Future Challenges, Cambridge University, Cambridge, U.K. (September 2010)

     
     

    "Small-scale heating events in the solar corona: forward modelling detectable emission in the TRACE pass-bands ." British Council N+N Workshop, Budapest, Hungary. (February 2004)

     
     Lectures
     

    "Mysteries of the solar corona." Rice University, Houston, TX. (January 2010)

     
     

    "The Sun and Space Weather." The Scottish Space School, Rice University, Houston, TX. (November 2010)

     
     Other
     

    "Non-equilibrium ionisation and its influence on spectral lines emitted from the solar atmosphere." Selection Panel for STFC Post-Doctoral Fellowships, London, U.K.. (February 2005)

     
     Posters
     

    "Effects of Ion Heating on Emission Measure of Coronal Loops in Active Region Cores." Solar Coronal Loops Workshop VII, Cambridge, UK. (July 2015) With Barnes, W. T.

     
     

    "A hybrid fluid-kinetic approach to modelling the solar corona." U.K. Solar Physics Meeting, Preston, U.K. (April 2007)

     
     

    "Radiative cooling of post-flare loops." U.K. Solar Physics Meeting, Birmingham, U.K. (April 2005)

     
     Seminar Speaker
     

    "What Powers the Dynamic Solar Atmosphere?." Rice University, Houston, TX. (October 2016)

     
     

    "Solar Flares and Space Weather.." Lamar University, Beaumont, TX. (March 2016)

     
     

    "Solar Flares: Explosive Plasma Physics.." University of Arizona, Tucson, AZ. (March 2016)

     
     

    "Solar Flares: Explosive Plasma Physics.." Dartmouth College, Hanover, NH. (February 2016)

     
     

    "What Do We Need to Solve the Coronal Heating Problem?." University of Arizona, Tucson, AZ. (February 2016)

     
     

    "Solar flares: plasma physics in an extreme environment." Grinnell College (February 2015).

     
     

    Seminar Speaker.  "Some challenges associated with numerical modeling of solar flares: plasma physics in an extreme environment,." Rice University, Houston, TX. (April 2013)

     
     

    Seminar Speaker.  "Some challenges associated with numerical modeling of solar flares: plasma physics in an extreme environment,." New Mexico State University, Las Cruces, NM. (October 2013)

     
     

    Seminar Speaker.  "2012, or how I learned to stop worrying and love the Sun." Rice University, Houston, TX. (February 2012)

     
     

    "Energy transfer by an enthalpy flux in the solar atmosphere." NASA Goddard Space Flight Center, Heliospheric Science Division Director's Seminar, Greenbelt, MD. (May 2010)

     
     

    "The dynamic solar corona." Rice University, Houston, TX. (January 2010)

     
     

    "A reinterpretation of the energy balance in EUV loops following new results from Hinode-EIS." George Mason University, Fairfax, VA. (February 2009)

     
     

    "A reinterpretation of the energy balance in EUV loops following new results from Hinode-EIS." Imperial College London, London, U.K. (March 2008)

     
     

    "Properties of radiatively cooling coronal loops." University College London, London, U.K. (February 2008)

     
     

    "A hybrid fluid-kinetic approach to modelling the solar atmosphere." Cambridge University, Cambridge, U.K. (February 2007)

     
     

    "A hybrid fluid-kinetic approach to modelling the solar atmosphere." University of St. Andrews, St. Andrews, U.K. (February 2007)

     
     

    "A hybrid fluid-kinetic approach to modelling the solar atmosphere." Imperial College London, London, U.K. (October 2006)

     
     

    "Hybrid fluid-kinetic models of the solar atmosphere." Warwick University, Warwick, U.K. (June 2006)

     
     

    "Determining the origin of robust scaling-laws in solar coronal loops." Imperial College London, London, U.K. (May 2005)

     
     

    "Properties of radiatively cooling coronal loops ." University of St. Andrews, St. Andrews, U.K. (December 2005)

     
     

    "Hydrodynamics of the solar atmosphere: a new treatment of optically-thin radiation." Cambridge University, Cambridge, U.K. (April 2003)

     
     

    "Non-equilibrium ion populations in a catastrophically cooling loop." Sheffield University, Sheffield, U.K. (July 2002)

     
     

    "Non-equilibrium ion populations in rapidly evolving plasma systems." Harvard University, Boston, MA. (November 2001)

     
     

    "Non-equilibrium ion populations in rapidly evolving plasma systems." U.S. Naval Research Labs., Washington D.C. (October 2001)

     
     Session Chair
     

    "Space Science, Astronomy & Cosmology.." American Physical Society (Texas Section), Beaumont, TX. (April 2016)

     
     

    "Chromosphere - Transition Region - Corona." Triennial Earth-Sun Summit (TESS), Indianapolis, IN. (April 2015)

     
     

    "Solar Coronal Loops Workshop VII." Cambridge, UK. (July 2015)

     
     

    "Solar Physics Division of the American Astronomical Society Meeting." Las Cruces, NM. (June 2011).

     
     

    "Coronal heating: new observational results and forward modelling." Royal Astronomical Society Discussion Meeting, London, U.K. (January 2008)

     
     

    "Solar kinetics and MHD." Solar Theory Discussion Meeting, Oxford, U.K. (February 2008)

     
     Workshops
     

    "Catastrophic cooling of coronal loops

     ." Coronal heating - using observables (flows and emission measure) to settle the question of steady vs. impulsive heating, International Space Science Institute (ISSI), Bern, Switzerland. (March 2014)

     
     

    "Large-scale active region models based on impulsive heating

     ." Coronal heating - using observables (flows and emission measure) to settle the question of steady vs. impulsive heating, International Space Science Institute (ISSI), Bern, Switzerland. (March 2014)

     
     

    "Low-frequency nanoflares and nanoflare trains

     ." Coronal heating - using observables (flows and emission measure) to settle the question of steady vs. impulsive heating, International Space Science Institute (ISSI), Bern, Switzerland. (March 2013)

     
     

    "Why does spatial resolution matter in numerical models of coronal heating?

     ." Coronal heating - using observables (flows and emission measure) to settle the question of steady vs. impulsive heating, International Space Science Institute (ISSI), Bern, Switzerland. (March 2013)

     
     

    "Diagnostics and spectral modeling of bulk flows in the solar atmosphere." Coronal heating - using observables (flows and emission measure) to settle the question of steady vs. impulsive heating, International Space Science Institute (ISSI), Bern, Switzerland. (February 2012)

     
     

    "Forward modeling the signatures of impulsive heating in the solar atmosphere

     ." Coronal heating - using observables (flows and emission measure) to settle the question of steady vs. impulsive heating, International Space Science Institute (ISSI), Bern, Switzerland. (February 2012)

     
     

    "HYDRAD: A numerical hydrodynamic and radiative emission model for the solar atmosphere ." Coronal loop modeling codes benchmarking group, U.S. Naval Research Labs., Washington D.C. (May 2009)

     
    Supervised Theses & Dissertations
     Shane Alpert, BS Bright dots in a sunspot penumbra. (2015) (Thesis or Dissertation Director)

     Jeffrey Reep, Ph.D. Solar flare spectral modeling. (2015) (Thesis or Dissertation Director)

     Rajesh Gandham, Ph.D. Computational and Applied Mathematics. (2015) (Committee Member)

     Brandon Mueller, M.Sc. Coronal heating as the driver of small-scale variability in the solar wind. (2015) (Thesis or Dissertation Director)

     Arturo Vargas, Ph.D. Hermite Methods: Algorithms, Acceleration, and Applications. (2017) (Committee Member)

     Alina Blinova, Ph.D. Atomic and Molecular Optics. (Committee Member)

     Shah Bahauddin, Ph.D. Understanding the energy balance of transition region structures observed by IRIS in non-equilibrium emission. (Thesis or Dissertation Director)

     Emilian Nica, Ph.D. Condensed Matter. (Committee Member)

     Lifei Liu, Ph.D. Condensed Matter. (Committee Member)

     Yajing Li, Ph.D. Condensed Matter. (Committee Member)

     Will Barnes, Ph.D. Impulsive heating in the solar atmosphere. (Thesis or Dissertation Director)

    Awards, Prizes, & Fellowships
     CAREER: Exploring new regimes of physics to constrain the properties of heating in the solar corona, National Science Foundation (May 2015)

     Scholar Athlete's Favorite Professor, Scholar Athlete (February 2015)

     Outstanding Faculty Associate, Martel College, Rice University (April 2011)

     Post-Doctoral Fellowship, Science and Technology Facilities Council (January 2006)

    Positions Held
     Committee Member, Coronal Loops Workshop Steering Committee. (2014 - 2016)

     Chair, Coronal Loops Workshop Steering Committee. (2016 - 2016)

     Executive Committee Member, Solar Physics Division of the American Astronomical Society. (2015 - 2016)

     Public Policy Committee Member, Solar Physics Division of the American Astronomical Society. (2013 - 2016)