Alfvén Pulse driven Cool Spicule-like Jets in the Sun's Atmosphere

Balveer Singh

Hosted by Department of Physics, Indian Institute of Technology (BHU), India on June 8, 2023


The complex magnetic structuring and highly dynamical nature of the solar atmosphere allow triggering of various cool spicule-like thin jets (T<105 K). These cool jets are basically collimated plasma ejecta that rise and fall quasi-periodically along the magnetic field lines in the Sun’s atmosphere. Several multiwavelength observations have been captured from space and ground based observatories revealing the evolution of these small scale cool jets and associated plasma processes (e.g., waves and oscillations, instabilities etc). Their physics can be understood extensively by performing numerical simulations. We numerically model such plasma jets in 2.5 D regime using the theory of Magnetohydrodynamics (MHD). Our model describes the formation/evolution of these jets and associated physical processes. We implement multiple Alfvén pulses of magnitudes 50-90 km/s in the solar chromosphere, which are found to be responsible for the triggering of these spicule-like jets. The applied Alfvén pulses generate the field-aligned perturbations due to ponderomotive force in the non-linear regime. These field-aligned perturbations are responsible for the generation of magnetoacoustic shocks in the upward direction in the model solar atmosphere. These magnetoacoustic shocks followed by the plasma motions essentially trigger the spicule-like cool, thin jets in the solar atmosphere. We analyse the formation mechanism, kinematics, and energetics of these spicule-like jets, which is consistent with various observational findings. We finally report the mass motions generated insitu quasi-periodic oscillations at the scale of 4.0 min above the solar transition region.

Co-Author: A.K. Srivastava

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