PREDNASAJUCI / LECTURER :

Sergo Lomineishvili

(1) Astronomical Institute, Slovak Academy of Sciences,
059 60 Tatranská Lomnica

NAZOV / TITLE :

Heating and Instability in Solar Spicules: Non-Ideal MHD Approach and Simulations

ABSTRAKT / ABSTRACT :

Studies in the last decade combining observations from Hinode, VAULT2.0, and the Interface
Region Imaging Spectrograph (IRIS) have shown that spicules—a widespread phenomenon in
the solar atmosphere—often appear in hotter lines such as Mg II, C II, and Si IV after
disappearing in chromospheric lines.

Observations indicate that spicules exhibit continuous transverse motion of their axes,
interpreted as Alfvén and/or magnetohydrodynamic (MHD) kink waves. The oscillation periods
and simplified growth-time estimates of unstable modes in spicules are comparable to their
lifetimes, making such studies particularly interesting. For instance, do type II (faster) spicules
disappear over a shorter timescale than their oscillation period? While no single mechanism
fully explains such strong damping of oscillations and the associated heating, ion-neutral
collisions and the Kelvin–Helmholtz instability (also known as dynamic kink instability) may
together contribute to rapid heating or destruction. This question remains open for discussion,
and we aim to take a step forward in addressing it.

We study spicules extending into the solar chromosphere, incorporating non-ideal (resistive)
MHD effects to broaden the scope of possible instabilities. We integrate these findings with
simulations (using MANCHA code models) for comparative analysis.