Connecting Spicules and Propagating Coronal Disturbances Using Radiative MHD Simulations of the Solar Atmosphere

<p dir="ltr">Spicules are ubiquitous, small-scale plasma jets that populate the lower solar atmosphere. They are seen prominently in chromospheric observations and also exhibit signatures in the transition region and lower corona. More recently, these highly dynamic spicular jets in observations have been reported to be associated with upward propagating EUV intensity perturbations in the corona. A similar link has been found in previous simulations. This can have important implications for understanding mass and energy transport in the solar atmosphere. However, the physical origin and properties of these Propagating Coronal Disturbances (PCDs), and their spicular connection, are not yet fully understood. In this ongoing work, we explore the connection of PCDs with spicules by performing 2D radiative MHD simulations using the Pencil Code, where a forest of spicules is self-consistently produced in the solar atmosphere powered by the subsurface convective processes. By using the technique of Lagrangian tracking on the simulated snapshots, we find that the convection generates “acceleration fronts” by several mechanisms, including, for example, (1) squeezing by granular buffeting, (2) collapse of granules, and (3) solar global modes, aided by magnetic reconnection. These acceleration fronts are also regions of strong compression or shocks that propagate outward through the solar atmosphere at the speed of slow magneto-acoustic waves. The passage of shock fronts successively through any point in the atmosphere produces saw-toothed velocity signals. We analyze wavelet power spectra for these modeled velocity signals sampled at several atmospheric heights in the simulations, along with other diagnostics, and use them to investigate how the slow MHD shock waves may be the common driver behind both PCDs and spicules.</p><p dir="ltr">Speaker: Sankalp Srivastava (Indian Institute of Astrophysics, Bangalore, India)</p><p dir="ltr">Link to ESPOS webpage:</p><p dir="ltr">https://espos.stream/2025/11/13/Srivastava/</p>