A Coronal Enhancement in the Extreme Ultraviolet

Boardman, William J.; Billings, Donald E.

doi:10.1086/150002

Cited by 17 publications

(1 citation statement)

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“…Analyses of absolute intensities, particularly in active regions on the limb, have shown that in general the central parts of active regions, at low heights, are hotter and denser than the more extensive surrounding material. Observations with sufficient spatial resolution show that the hot denser central regions are associated with low lying loop structures and the cooler less dense regions with more extensive loops (see, for example, Boardman & Billings 1969;Mason 1975;Vaiana et al 1973). One of the characteristic aspects they appear to be isothermal over a large range of their height -observations in emission lines formed at different temperatures reveal distinctly different features.…”

Section: Odels Based On Observed Conditionsmentioning

confidence: 99%

A Discussion on the physics of the solar atmosphere - The structure and energy balance of solar active regions

Jordan

1976

Phil. Trans. R. Soc. Lond. A

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The interpretation of the emission measures calculated from e.u.v. and X-ray line intensities is discussed. A general method for deriving the temperature and density structure and energy balance in either the quiet Sun or active regions is given. In particular simple relations are found between the coronal temperature, the pressure in the chromosphere—corona transition region, P 0 , the conductive flux at P 0 , the mechanical energy dissipated above P 0 and the radiation losses above P 0 . A range of models for quiet and active regions is given. The rate of change of the mechanical energy deposition as a function of height is used to find empirical damping lengths which are compared with those expected from either the conduction damping of sound waves or the viscous damping of Alfven waves. The wave frequencies and peak amplitude velocities required to satisfy both the empirical and theoretical damping lengths and energy deposition rates are discussed.

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Section: Odels Based On Observed Conditionsmentioning

confidence: 99%