0000000000116190

AUTHOR

C. D. Johnston

showing 2 related works from this author

A fast multi-dimensional magnetohydrodynamic formulation of the transition region adaptive conduction (TRAC) method

2021

We have demonstrated that the Transition Region Adaptive Conduction (TRAC) method permits fast and accurate numerical solutions of the field-aligned hydrodynamic equations, successfully removing the influence of numerical resolution on the coronal density response to impulsive heating. This is achieved by adjusting the parallel thermal conductivity, radiative loss, and heating rates to broaden the transition region (TR), below a global cutoff temperature, so that the steep gradients are spatially resolved even when using coarse numerical grids. Implementing the original 1D formulation of TRAC in multi-dimensional magnetohydrodynamic (MHD) models would require tracing a large number of magne…

Sun: flaresMagnetohydrodynamics (MHD)010504 meteorology & atmospheric sciencescorona [Sun]Field lineNDASFOS: Physical scienceschromosphere [Sun]Astrophysics01 natural sciencestransition region [Sun]0103 physical sciencesRadiative transferQB AstronomyMagnetohydrodynamic driveflares hydrodynamics [Sun]Sun: transition region010303 astronomy & astrophysicsSolar and Stellar Astrophysics (astro-ph.SR)QC0105 earth and related environmental sciencescomputer.programming_languageQBPhysicsSun: coronaSun: chromosphereAstronomy and AstrophysicsTRACCoronal loopThermal conductionComputational physicsMagnetic fieldQC PhysicsAstrophysics - Solar and Stellar AstrophysicsSpace and Planetary ScienceHydrodynamicsMagnetohydrodynamicscomputerSettore FIS/06 - Fisica Per Il Sistema Terra E Il Mezzo Circumterrestre
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Chromospheric evaporation and phase mixing of Alfvén waves in coronal loops

2020

Phase mixing of Alfv\'en waves has been studied extensively as a possible coronal heating mechanism but without the full thermodynamic consequences considered self-consistently. It has been argued that in some cases, the thermodynamic feedback of the heating could substantially affect the transverse density gradient and even inhibit the phase mixing process. In this paper, we use MHD simulations with the appropriate thermodynamical terms included to quantify the evaporation following heating by phase mixing of Alfv\'en waves in a coronal loop and the effect of this evaporation on the transverse density profile. The numerical simulations were performed using the Lare2D code. We set up a 2D l…

Sun: generalatmosphere [Sun]Magnetohydrodynamics (MHD)corona [Sun]010504 meteorology & atmospheric sciencesDensity gradientThermodynamic equilibriumT-NDASEvaporationAstrophysics01 natural sciencesAlfvén wave0103 physical sciencesgeneral [Sun]QB AstronomyAstrophysics::Solar and Stellar AstrophysicsSun: oscillations010303 astronomy & astrophysicsQCQB0105 earth and related environmental sciencesPhysicsSun: coronaoscillations [Sun]Astronomy and AstrophysicsMechanicsCoronal loopDissipationTransverse planeQC PhysicsAstrophysics - Solar and Stellar AstrophysicsSpace and Planetary SciencePhysics::Space PhysicsWavesMagnetohydrodynamicsBDCSun: atmosphere
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