Temperature and density structure of hot and cool loops derived from the analysis of TRACE data

We study the transversal structure (in particular the. lamentation) and the longitudinal plasma strati. cation in two sets of solar coronal loops observed with TRACE in the 171 and 195 Angstrom passbands. The density strati. cation and the thermal structuring of the plasma along the fibrils that form the loops are derived using two techniques simultaneously: (1) a filter ratio diagnostic (195/171 Angstrom) and (2) modeling intensity profiles along the fibrils with hydrostatic models; in both techniques we remove the background flux. We find consistent values of temperature and density with both methods in the coronal structures selected. We find evidence of a very warm fibril (T approximate to 5 x 10(6) K) and of rather cold ones (T approximate to 2 x 10(5) K). The hot fibril appears to have a thermal structure with a maximum at the apex compatible with temperature and density strati. cation, dictated by energy balance, typical of a nonisothermal hydrostatic loop. The cold fibrils appear to be isothermal and are probably in dynamical conditions.