TRACE-derived Temperature and Emission Measure Profiles along Long-lived Coronal Loops: The Role of Filamentation.

In a recent Letter, Lenz et al. have shown evidence of uniform temperature along steady long coronal loops observed by TRACE in two different passbands (171 and 195 Å filters). We propose that such a piece of evidence can be explained by the subarcsecond structuring of the loops across the magnetic field lines. In this perspective, we present a model of a bundle of six thin parallel hydrostatic filaments with temperature stratification dictated by detailed energy balance and with temperatures at their apex ranging between 0.8 and 5 MK. If analyzed as a single loop, the bundle would appear isothermal along most of its length.