THE FIRST MEASUREMENT OF THE ADIABATIC INDEX IN THE SOLAR CORONA USING TIME-DEPENDENT SPECTROSCOPY OF HINODE/EIS OBSERVATIONS
- CFSA, Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom)
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 {gamma}{sub eff} = 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.
- OSTI ID:
- 21560536
- Journal Information:
- Astrophysical Journal Letters, Vol. 727, Issue 2; Other Information: DOI: 10.1088/2041-8205/727/2/L32; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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