Thermal non-equilibriuem revealed by periodic pulses of random amplitudes in solar coronal loops

Abstract

We recently detected variations in extreme ultraviolet intensity in coronal loops repeating with periods of several hours. Models of loops including stratified and quasi-steady heating predict the development of a state of thermal non-equilibrium (TNE): cycles of evaporative upflows at the footpoints followed by falling condensations at the apex. Based on Fourier and wavelet analysis, we demonstrate that the observed periodic signals are indeed not signatures of vibrational modes. Instead, superimposed on the power law expected from the stochastic background emission, the power spectra of the time series exhibit the discrete harmonics and continua expected from periodic trains of pulses of random amplitudes. These characteristics reinforce our earlier interpretation of these pulsations as being aborted TNE cycles.

References in corpus (20)

• Key Aspects of Coronal Heating
• Coronal rain as a marker for coronal heating mechanisms
• Solar Corona Loop Studies with AIA: I. Cross-Sectional Temperature Structure
• Coronal Heating, Weak MHD Turbulence and Scaling Laws
• The multi-thermal and multi-stranded nature of coronal rain
• Can Thermal Nonequilibrium Explain Coronal Loops?
• Dynamics of solar coronal loops II. Catastrophic cooling and high-speed downflows
• Quasi-periodic pulsations in solar and stellar flares: re-evaluating their nature in the context of power-law flare Fourier spectra
• On The Fourier And Wavelet Analysis Of Coronal Time Series
• Evidence for evaporation-incomplete condensation cycles in warm solar coronal loops
• Quasi-Periodic Pulsations in Solar Flares: new clues from the Fermi Gamma-Ray Burst Monitor
• Long-period intensity pulsations in the solar corona during activity cycle 23
• An ALMA Disk Mass for the Candidate Protoplanetary Companion to FW Tau
• On the Accuracy of the Differential Emission Measure Diagnostics of Solar Plasmas. Application to AIA/SDO. Part II: Multithermal plasmas
• Modeling the Line-of-Sight Integrated Emission in the Corona: Implications for Coronal Heating
• On the Accuracy of the Differential Emission Measure Diagnostics of Solar Plasmas. Application to AIA/SDO. Part I: Isothermal plasmas
• Can the Differential Emission Measure constrain the timescale of energy deposition
• Coronal Fourier power spectra: implications for coronal seismology and coronal heating
• Can Large Time Delays Observed in Light Curves of Coronal Loops be Explained by Impulsive Heating?
• On the importance of background subtraction in the analysis of coronal loops observed with TRACE

Cited by in corpus (11)

• On the occurrence of thermal non-equilibrium in coronal loops
• Long-Period Intensity Pulsations in Coronal Loops Explained by Thermal Non-Equilibrium Cycles
• The Coronal Monsoon: Thermal Nonequilibrium Revealed by Periodic Coronal Rain
• Coronal rain in randomly heated arcades
• Multi-scale observations of thermal non-equilibrium cycles in coronal loops
• A highly dynamic small-scale jet in a polar coronal hole
• On the spectroscopic detection of periodic plasma flows in loops undergoing thermal non-equilibrium
• Temporal evolution of oscillating coronal loops
• Magnetic field inference in active region coronal loops using coronal rain clumps
• A Global Survey of EUV Corona Power Spectra
• Thermal Non-equilibrium Cycles in a Non-eruptive Pseudo-Streamer