Electron density and temperature structure of two limb active regions observed by SOHO-CDS

The analysis of two active regions on the limb using observations from SOHO -CDS allows us to determine the electron density and temperature distributi on of the coronal emission. We find that the active regions have hot cores (3 x 10(6) K) with larger cooler (10(6) K) loop structures extending above the limb. The electron number density, determined using the Si X diagnostic line ratio, is found to be highest in the active region core (greater than 2.3 x 10(9) cm(-3)). Electron number density values are determined for a r ange of spectral lines from different ions and are found to increase with t emperature between 0.8 and 2.5 x 10(6) K. These results are consistent with recent models of enhanced heating along the compact core of active regions , where the magnetic field shear is strongest.