Resonant Excitation of Disk Oscillations in Deformed Disks V: Effects of Dissipative Process

TL;DR

This paper investigates how dissipative processes influence resonant excitation of oscillations in deformed relativistic disks, revealing that dissipation generally reduces growth rates but can also induce excitation under certain conditions.

Contribution

It demonstrates that dissipation affects wave excitation in deformed disks, showing both suppression and induction of oscillations depending on frequency conditions.

Findings

Dissipation decreases growth rates when resonance conditions are met.

Dissipation can induce oscillation excitation when frequency deviations are large.

The excitation mechanism is related to double-diffusive instability.

Abstract

It is suggested that a set of positive- and negative-energy oscillations can be resonantly excited in the inner region of deformed (warped or eccentric) relativistic disks. In this paper we examine how a dissipative process affects on this wave excitation process. The results show that when the resonant condition in frequency is roughly satisfied and thus the oscillations are excited, introduction of a dissipative process works so as to decrease the growth rate of the oscillations. When the frequency difference of the two oscillations deviates more than a certain amount from that required by resonant condition, however, the oscillations are excited by introduction of dissipative process. This excitation by dissipative process can be understood as a special example of the double-diffusive instability.