Speaker
Description
First Name: Sanghita
Last Name: Chandra
Email Address: chandra@mps.mpg.de
Affiliation: Max Planck Institute for Solar System Research
All Authors: Sanghita Chandra, Robert Cameron, Damien Przybylski, Sami K. Solanki
Abstract: It has been suggested that spicules play a role in coronal heating, with reports of an association with transition region (e.g. Si IV emission) and coronal emission, observable in EUV passbands with Solar Orbiter. Understanding spicules has been difficult using observations alone. Realistic 3D simulations now help overcome these limits. We present the first statistical analysis of synthetic spicules from MURaM-ChE simulations, which reproduce key features of chromospheric dynamics. The non-equilibrium hydrogen treatment enables examination of 3D spicule geometry. Using a new Hα proxy, we identify numerous off-limb spicules and their on-disk counterparts in an enhanced-network simulation. We statistically analyze 58 spicules (types I and II) and compare them with earlier studies using Ca II H and Hα observations. The synthetic spicules show morphological properties and lifetimes broadly consistent with observations. To probe the underlying structure, we examine selected spicules using the Hα-proxy opacity. One illustrative spicule, with an apparent 190 km/s velocity, shows a sheet-like morphology. We demonstrate that such extreme apparent speeds arise not from true mass motion but from a rippling plasma sheet seen along the line of sight. The sheet lies at a quasi-separatrix layer (QSL). Whether a spicule appears sheet- or tube-like depends strongly on the Doppler shift used for observation, and their on-disk counterparts often display structures distinct from the spicules themselves. We synthesize 174 ˚A emission to assess the spicules’ multi-thermal nature which enables comparison with Solar Orbiter /EUI.