Solar limb brightening at millimeter wavelengths

Previous models of microwave limb brightening have omitted the alignment of spicules along supergranule boundaries, have neglected the high temperature sheath around spicules, and have assumed an interspicular medium which was averaged over chromospheric network and non-network regions. We present a model which includes these factors. By constraining the model to conform to results from earlier UV and optical studies we are effectively left with two free parameters: the temperature at the core of the spicules, Tc .... and (at solar minimum), the interspicular chromospheric network density model of the lower transition zone. The absence of limb brightening at the short millimeter wavelengths implies Tcor~ ~< 6000 k. Differences between the model and certain deconvolved observations near 9 mm are expected as a consequence of an extension of emission beyond the optical limb, predicted by the model, which affects the accuracy of the deconvolution technique. Unlike models which assume homogeneous spicules in a random distribution, ours does not require an abnormally high spicule area.

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Solar limb brightening at millimeter wavelengths

Cited by 8 publications

References 10 publications

The Quiet Sun at cm- and mm-Wavelengths

The Quiet Sun at cm- and mm-Wavelengths

Overview of Infrared Solar Physics

Microwave solar limb brightening

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