  In the recent work of Nakariakov et al. (2004), it has been shown that the
time dependences of density and velocity in a flaring loop contain pronounced
quasi-harmonic oscillations associated with the 2nd harmonic of a standing slow
magnetoacoustic wave. That model used a symmetric heating function (heat
deposition was strictly at the apex). This left outstanding questions: A) is
the generation of the 2nd harmonic a consequence of the fact that the heating
function was symmetric? B) Would the generation of these oscillations occur if
we break symmetry? C) What is the spectrum of these oscillations? Is it
consistent with a 2nd spatial harmonic? The present work (and partly Tsiklauri
et al. (2004b)) attempts to answer these important outstanding questions.
Namely, we investigate the physical nature of these oscillations in greater
detail: we study their spectrum (using periodogram technique) and how heat
positioning affects the mode excitation. We found that excitation of such
oscillations is practically independent of location of the heat deposition in
the loop. Because of the change of the background temperature and density, the
phase shift between the density and velocity perturbations is not exactly a
quarter of the period, it varies along the loop and is time dependent,
especially in the case of one footpoint (asymmetric) heating. We also were able
to model successfully SUMER oscillations observed in hot coronal loops.
