Effects of Stratification and Flows on P1/P2 Ratios and Anti-Node Shifts within Closed Loop Structures

TL;DR

This paper extends a magneto-seismological method to analyze how stratification and flows affect wave properties in solar atmospheric structures, enabling more precise plasma diagnostics through observed wave ratios and anti-node shifts.

Contribution

It generalizes a novel technique to infer density profiles from harmonic ratios, accounting for flows and stratification, with predictions of anti-node shifts in solar plasma structures.

Findings

Wave period ratios deviate from harmonic ratios in stratified structures.

Significant anti-node shifts of up to 10 Mm are predicted due to flows.

The method shows strong agreement with recent observational data.

Abstract

The solar atmosphere is a dynamic environment, constantly evolving to form a wide range of magnetically dominated structures (coronal loops, spicules, prominences, etc.) which cover a significant percentage of the surface at any one time. Oscillations and waves in many of these structures are now widely observed and have led to the new analytic technique of solar magneto-seismology, where inferences of the background conditions of the plasma can be deduced by studying magneto-hydrodynamic (MHD) waves. Here, we generalise a novel magneto-seismological method designed to infer the density distribution of a bounded plasma structure from the relationship of its fundamental and first harmonics. Observations of the solar atmosphere have emphatically shown that stratification, leading to complex density profiles within plasma structures, is common thereby rendering this work instantly accessible to solar physics. We show, in a dynamic waveguide, how the period ratio differs from the idealised harmonic ratios prevalent in homogeneous structures. These ratios show strong agreement with recent observational work. Next, anti-node shifts are also analysed. Using typical scaling parameters for bulk flows within atmospheric waveguides, e.g., coronal loops, it is found that significant anti-node shifts can be predicted, even to the order of 10 Mm. It would be highly encouraged to design specific observations to confirm the predicted anti-node shifts and apply the developed theory of solar magneto-seismology to gain more accurate waveguide diagnostics of the solar atmosphere.