Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inferring flare loop parameters with measurements of standing sausage
  modes   Standing fast sausage modes in flare loops were suggested to account for a
considerable number of quasi-periodic pulsations (QPPs) in the light curves of
solar flares. This study continues our investigation into the possibility to
invert the measured periods $P$ and damping times $\tau$ of sausage modes to
deduce the transverse Alfv\'en time $R/v_{\rm Ai}$, density contrast $\rho_{\rm
i}/\rho_{\rm e}$, and the steepness of the density distribution transverse to
flare loops. A generic dispersion relation (DR) governing linear sausage modes
is derived for pressureless cylinders where density inhomogeneity of arbitrary
form takes place within the cylinder. We show that in general the inversion
problem is under-determined for QPP events where only a single sausage mode
exists, be the measurements spatially resolved or unresolved. While $R/v_{\rm
Ai}$ can be inferred to some extent, the range of possible steepness parameters
may be too broad to be useful. However, for spatially resolved measurements
where an additional mode is present, it is possible to deduce self-consistently
$\rho_{\rm i}/\rho_{\rm e}$, the profile steepness, and the internal Alfv\'en
speed $v_{\rm Ai}$. We show that at least for a recent QPP event that involves
a fundamental kink mode in addition to a sausage one, flare loop parameters are
well constrained, even if the specific form of the transverse density
distribution remains unknown. We conclude that spatially resolved, multi-mode
QPP measurements need to be pursued for inferring flare loop parameters.

2
The categories of this paper are: math
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn