# Slow-Mode Oscillations of Hot Loops Excited at Flaring Footpoints

## TL;DR

This study presents observational evidence that slow-mode oscillations in hot coronal loops are excited by impulsive heating events at the loop footpoints, linking small flares to loop oscillations.

## Contribution

It provides the first clear observational evidence that slow-mode standing waves are triggered by footpoint microflares in hot coronal loops.

## Key findings

- Damped Doppler shift oscillations detected in Fe XIX line.
- Oscillations triggered by small flare at loop footpoint.
- Supports impulsive heating as excitation mechanism.

## Abstract

The analysis of a hot loop oscillation event using SOHO/SUMER, GOES/SXI, and RHESSI observations is presented. Damped Doppler shift oscillations were detected in the Fe XIX line by SUMER, and interpreted as a fundamental standing slow mode. The evolution of soft X-ray emission from GOES/SXI and hard X-ray sources from RHESSI suggests that the oscillations of a large loop are triggered by a small flare, which may be produced by interaction (local reconnection) of this large loop with a small loop at its footpoint. This study provides clear evidence supporting our early conjecture that the slow-mode standing waves in hot coronal loops are excited by impulsive heating (small or microflares) at the loop's footpoint.