The first measurement of the adiabatic index in the solar corona using time-dependent spectroscopy of hinode/eis observations
Van Doorsselaere, Tom, Wardle, Nick, Del Zanna, Giulio, Jansari, Kishan, Verwichte, E. (Erwin) and Nakariakov, V. M. (Valery M.). (2011) The first measurement of the adiabatic index in the solar corona using time-dependent spectroscopy of hinode/eis observations. The Astrophysical Journal. Letters, Vol.727 (No.2). L32. ISSN 2041-8205Full text not available from this repository.
Official URL: http://dx.doi.org/10.1088/2041-8205/727/2/L32
We use observations of a slow magnetohydrodynamic wave in the corona to determine for the first time the value of the effective adiabatic index, using data from the Extreme-ultraviolet Imaging Spectrometer on board Hinode. We detect oscillations in the electron density, using the CHIANTI atomic database to perform spectroscopy. From the time-dependent wave signals from multiple spectral lines the relationship between relative density and temperature perturbations is determined, which allows in turn to measure the effective adiabatic index to be γeff = 1.10 ± 0.02. This confirms that the thermal conduction along the magnetic field is very efficient in the solar corona. The thermal conduction coefficient is measured from the phase lag between the temperature and density, and is shown to be compatible with Spitzer conductivity.
|Item Type:||Journal Article|
|Subjects:||Q Science > QB Astronomy
Q Science > QC Physics
|Divisions:||Faculty of Science > Physics|
|Library of Congress Subject Headings (LCSH):||Adiabatic invariants, Sun -- Corona, Solar oscillations, Astronomical spectroscopy|
|Journal or Publication Title:||The Astrophysical Journal. Letters|
|Publisher:||Institute of Physics Publishing, Inc.|
|Access rights to Published version:||Restricted or Subscription Access|
|Funder:||European Community (EC), Engineering and Physical Sciences Research Council (EPSRC)|
|Grant number:||220555 (EC)|
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