Oran R., B. van der Holst, E. Landi, M. Jin, I. V. Sokolov, T. I. Gombosi, (2013), A Global Wave-driven Magnetohydrodynamic Solar Model with a Unified Treatment of Open and Closed Magnetic Field Topologies, The Astrophysical Journal, 778, 176, doi:10.1088/0004-637X/778/2/176

Abstract

We describe, analyze, and validate the recently developed Alfvén Wave Solar Model, a three-dimensional global model starting from the top of the chromosphere and extending into interplanetary space (out to 1-2 AU). This model solves the extended, two-temperature magnetohydrodynamics equations coupled to a wave kinetic equation for low-frequency Alfvén waves. In this picture, heating and acceleration of the plasma are due to wave dissipation and to wave pressure gradients, respectively. The dissipation process is described by a fully developed turbulent cascade of counterpropagating waves. We adopt a unified approach for calculating the wave dissipation in both open and closed magnetic field lines, allowing for a self-consistent treatment in any magnetic topology. Wave dissipation is the only heating mechanism assumed in the model; no geometric heating functions are invoked. Electron heat conduction and radiative cooling are also included. We demonstrate that the large-scale, steady state (in the corotating frame) properties of the solar environment are reproduced, using three adjustable parameters: the Poynting flux of chromospheric Alfvén waves, the perpendicular correlation length of the turbulence, and a pseudoreflection coefficient. We compare model results for Carrington rotation 2063 (2007 November-December) with remote observations in the extreme-ultraviolet and X-ray ranges from the Solar Terrestrial Relations Observatory , Solar and Heliospheric Observatory , and Hinode spacecraft and with in situ measurements by Ulysses . The results are in good agreement with observations. This is the first global simulation that is simultaneously consistent with observations of both the thermal structure of the lower corona and the wind structure beyond Earth's orbit.

Authors (sorted by name)

Gombosi Jin Landi Oran Sokolov van der Holst

Journal / Conference

The Astrophysical Journal

Acknowledgments

The work presented in this paper was supported by NSF CDI grant AGS-1027192 and NSF Space Weather Research grant AGS-1322543. We express our gratitude to Cooper Downs for useful suggestions and discussions. The simulations performed in this work were made possible thanks to the NASA Advanced Supercomputing Division, which granted us access to the Pleiades supercomputing cluster. We thank NASA's CDAWeb for supplying us with Ulysses observations. Analysis of radiative processes was made possible through the use of the CHIANTI atomic database. CHIANTI is a collaborative project involving George Mason University, the University of Michigan (US), and the University of Cambridge (UK). We thank the Hinode (Solar-B) team for supplying us with XRT and EIS data. Hinode is a Japanese mission developed and launched by ISAS/JAXA, with NAOJ as domestic partner and NASA and STFC (UK) as international partners. It is operated by these agencies in cooperation with ESA and NSC (Norway).

Grants

AGS-1027192 AGS-1322543

Bibtex

@article{0004-637X-778-2-176,
  author={R. Oran and B. van der Holst and E. Landi and M. Jin and I. V. Sokolov and T. I. Gombosi},
  title={A Global Wave-driven Magnetohydrodynamic Solar Model with a Unified Treatment of Open and Closed Magnetic Field Topologies},
  journal={The Astrophysical Journal},
  volume={778},
  number={2},
  doi={10.1088/0004-637X/778/2/176},
  pages={176},
  url={http://stacks.iop.org/0004-637X/778/i=2/a=176},
  year={2013},
  abstract={We describe, analyze, and validate the recently developed Alfvén Wave Solar Model, a three-dimensional global model starting from the top of the chromosphere and extending into interplanetary space (out to 1-2 AU). This model solves the extended, two-temperature magnetohydrodynamics equations coupled to a wave kinetic equation for low-frequency Alfvén waves. In this picture, heating and acceleration of the plasma are due to wave dissipation and to wave pressure gradients, respectively. The dissipation process is described by a fully developed turbulent cascade of counterpropagating waves. We adopt a unified approach for calculating the wave dissipation in both open and closed magnetic field lines, allowing for a self-consistent treatment in any magnetic topology. Wave dissipation is the only heating mechanism assumed in the model; no geometric heating functions are invoked. Electron heat conduction and radiative cooling are also included. We demonstrate that the large-scale, steady state (in the corotating frame) properties of the solar environment are reproduced, using three adjustable parameters: the Poynting flux of chromospheric Alfvén waves, the perpendicular correlation length of the turbulence, and a pseudoreflection coefficient. We compare model results for Carrington rotation 2063 (2007 November-December) with remote observations in the extreme-ultraviolet and X-ray ranges from the Solar Terrestrial Relations Observatory , Solar and Heliospheric Observatory , and Hinode spacecraft and with in situ measurements by Ulysses . The results are in good agreement with observations. This is the first global simulation that is simultaneously consistent with observations of both the thermal structure of the lower corona and the wind structure beyond Earth's orbit.}
}