The fine-scale structure of chromospheric jets and their formation process

  • Nived Vilangot Nhalil

Student thesis: Doctoral ThesisDoctor of Philosophy


Spicules were first discovered in 1877 by Angelo Secchi. They are ubiquitous in the solar chromosphere. Recent progress in adaptive optics and image processing techniques provided an unprecedented view of the chromosphere. Combining such observations with state-of-art numerical simulation has improved our understanding of the spicules. The seeing-free observation obtained by the Hinode satellite led to the discovery of a new type of spicules known as Type II spicules. Their sudden disappearance from chromospheric passbands made them a new candidate for coronal heating. But their contribution to heating the corona is still under debate. In this thesis, we present the evidence of heating associated with Type II spicule in the transition region and corona. When observed in transition region lines, Type II spicules show intensity enhancement and broadening. In the corona, we found intensity enhancement associated with a collection of Type II spicules. Another important candidate for coronal heating is nanoflares. Our study on the energetics of nanoflare-like brightening in the transition region shows that they don’t produce enough energy to sustain the million-kelvin corona.

Date of AwardJul 2023
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SponsorsArmagh Observatory and Planetarium
SupervisorJohn Doyle (Supervisor), Michail Mathioudakis (Supervisor) & Gavin Ramsay (Supervisor)


  • Sun
  • solar active regions
  • solar atmosphere
  • solar flare
  • chromosphere

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