The Coronal Monsoon: Thermal Nonequilibrium Revealed by Periodic Coronal Rain

Abstract

We report on the discovery of periodic coronal rain in an off-limb sequence of {\it Solar Dynamics Observatory}/Atmospheric Imaging Assembly images. The showers are co-spatial and in phase with periodic (6.6~hr) intensity pulsations of coronal loops of the sort described by Auchere et al. (2014) and Froment et al. (2015, 2017). These new observations make possible a unified description of both phenomena. Coronal rain and periodic intensity pulsations of loops are two manifestations of the same physical process: evaporation / condensation cycles resulting from a state of thermal nonequilibrium (TNE). The fluctuations around coronal temperatures produce the intensity pulsations of loops, and rain falls along their legs if thermal runaway cools the periodic condensations down and below transition-region (TR) temperatures. This scenario is in line with the predictions of numerical models of quasi-steadily and footpoint heated loops. The presence of coronal rain -- albeit non-periodic -- in several other structures within the studied field of view implies that this type of heating is at play on a large scale.

arXiv commentBy mistake, this article was originally submitted as a replacement (version v4) of arXiv:1608.03789. This latter was then replaced with a correct v5 (identical to v3) The present paper was then properly submitted as a new submission (this version)

References in corpus (42)

• CHIANTI - An atomic database for Emission Lines. Version 8
• 25 Years of Self-Organized Criticality: Solar and Astrophysics
• The Dynamic Formation of Prominence Condensations
• Observing the fine structure of loops through high resolution spectroscopic observations of coronal rain with the CRISP instrument at the Swedish Solar Telescope
• Coronal rain as a marker for coronal heating mechanisms
• An Ab Initio approach to Solar Coronal Loops
• Formation and plasma circulation of solar prominences
• Evidence for Widespread Cooling in an Active Region Observed with the SDO Atmospheric Imaging Assembly
• Formation of Solar Filaments by Steady and Nonsteady Chromospheric Heating
• The multi-thermal and multi-stranded nature of coronal rain
• Patterns of Nanoflare Storm Heating Exhibited by an Active Region Observed with SDO/AIA
• Active region transition region loop populations and their relationship to the corona
• Can Thermal Nonequilibrium Explain Coronal Loops?
• A large-scale search for evidence of quasi-periodic pulsations in solar flares
• 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
• Multidimensional modeling of coronal rain dynamics
• Evidence for evaporation-incomplete condensation cycles in warm solar coronal loops
• Transverse oscillations of loops with coronal rain observed by Hinode/SOT
• Dynamics of coronal rain and descending plasma blobs in solar prominences: II. partially ionized case
• Quasi-Periodic Pulsations in Solar Flares: new clues from the Fermi Gamma-Ray Burst Monitor
• Coronal rain in magnetic arcades: Rebound shocks, Limit cycles, and Shear flows
• On-disk coronal rain
• Long-period intensity pulsations in the solar corona during activity cycle 23
• An ALMA Disk Mass for the Candidate Protoplanetary Companion to FW Tau
• 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 II: Multithermal plasmas
• Long-Period Intensity Pulsations in Coronal Loops Explained by Thermal Non-Equilibrium Cycles
• On the Accuracy of the Differential Emission Measure Diagnostics of Solar Plasmas. Application to AIA/SDO. Part I: Isothermal plasmas
• Dynamics of coronal rain and descending plasma blobs in solar prominences: I. Fully ionised case
• Continuous upflows and sporadic downflows observed in active regions
• Can the Differential Emission Measure constrain the timescale of energy deposition
• Coronal Fourier power spectra: implications for coronal seismology and coronal heating
• Observing the formation of flare-driven coronal rain
• Coronal rain in magnetic bipolar weak fields
• Simulating coronal condensation dynamics in 3D
• Spectroscopy of very hot plasma in non-flaring parts of a solar limb active region: spatial and temporal properties
• Formation and evolution of coronal rain observed by SDO/AIA on February 22, 2012
• Observations of Transient Active Region Heating with Hinode
• Thermal non-equilibriuem revealed by periodic pulses of random amplitudes in solar coronal loops
• Can Large Time Delays Observed in Light Curves of Coronal Loops be Explained by Impulsive Heating?

Cited by in corpus (28)

• On the occurrence of thermal non-equilibrium in coronal loops
• Observations of Solar Coronal Rain in Null Point Topologies
• The Distinction Between Thermal Nonequilibrium and Thermal Instability
• The effects of numerical resolution, heating timescales and background heating on thermal non-equilibrium in coronal loops
• Thermal instabilities: Fragmentation and field misalignment of filament fine structure
• Multi-scale observations of thermal non-equilibrium cycles in coronal loops
• Electron Beams Cannot Directly Produce Coronal Rain
• Self-consistent 3D radiative MHD simulations of coronal rain formation and evolution
• Modelling the solar transition region using an adaptive conduction method
• Understanding Heating in Active Region Cores through Machine Learning I. Numerical Modeling and Predicted Observables
• Spatial and Temporal Analysis of Quiescent Coronal Rain over an Active Region
• Two-dimensional simulations of coronal rain dynamics. I. Model with vertical magnetic field and an unbounded atmosphere
• Formation of coronal rain triggered by impulsive heating associated with magnetic reconnection
• Prevalence of Thermal Non-Equilibrium over an Active Region
• Neutral Helium Triplet Spectroscopy of Quiescent Coronal Rain with Sensitivity Estimates for Spectropolarimetric Magnetic Field Diagnostics
• EUV fine structure and variability associated with coronal rain revealed by Solar Orbiter/EUI HRIEUV and SPICE
• Geometric Assumptions in Hydrodynamic Modeling of Coronal and Flaring Loops
• Relation of coronal rain originating from coronal condensations to interchange magnetic reconnection
• On-disk solar coronal condensations facilitated by magnetic reconnection between open and closed magnetic structures
• On the spectroscopic detection of periodic plasma flows in loops undergoing thermal non-equilibrium
• Magnetic field inference in active region coronal loops using coronal rain clumps
• Revisiting the formation mechanism for coronal rain from previous studies
• Modeling of Condensations in Coronal Loops Produced by Impulsive Heating
• Spatiotemporal Low FIP Abundance: A Catalyst for Coronal Condensation
• Coronal kink oscillations and photospheric driving: combining SolO/EUI and SST/CRISP high-resolution observations
• The Equilibrium of Coronal Loops Near Separatrices
• On the Effect of Coronal Rain on Decayless Kink Oscillations of Coronal Loops
• Thermal Non-equilibrium Cycles in a Non-eruptive Pseudo-Streamer