Journal ArticleHigh-resolution Imaging Spectroscopy of a Tiny Sigmoidal Minifilament EruptionWang, Jiasheng; Lee, Jeongwoo; Chae, Jongchul; Cao, Wenda; Wang, Haimin<title>Abstract</title> <p>Minifilament eruptions producing small jets and microflares have mostly been studied based on coronal observations at extreme-ultraviolet and X-ray wavelengths. This study presents chromospheric plasma diagnostics of a quiet-Sun minifilament of size ∼ 2″ × 5″ with a sigmoidal shape and an associated microflare observed on 2021 August 7 17:00 UT using high temporal and spatial resolution spectroscopy from the Fast Imaging Solar Spectrograph (FISS) and high-resolution magnetograms from the Near InfraRed Imaging Spectropolarimeter (NIRIS) installed on the 1.6 m Goode Solar Telescope at Big Bear Solar Observatory. Using FISS H<italic>α</italic>and Ca<sc>ii</sc>8542 Å line spectra at the time of the minifilament activation we determined a temperature of 8600 K and a nonthermal speed of 7.9 km s⁻¹. During the eruption, the minifilament was no longer visible in the Ca<sc>ii</sc>8542 Å line, and only the H<italic>α</italic>line spectra were used to find the temperature of the minifilament, which reached 1.2 × 10⁴K and decreased afterward. We estimated thermal energy of 3.6 × 10²⁴erg from the maximum temperature and kinetic energy of 2.6 × 10²⁴erg from the rising speed (18 km s⁻¹) of the minifilament. From the NIRIS magnetograms we found small-scale flux emergence and cancellation coincident with the minifilament eruption, and the magnetic energy change across the conjugate footpoints reaches 7.2 × 10²⁵erg. Such spectroscopic diagnostics of the chromospheric minifilament complement earlier studies of minifilament eruptions made using coronal images.</p>American Astronomical Society2024-10-0110577601The Astrophysical Journal97411230004-637Xhttps://doi.org/10.3847/1538-4357/ad74f32309939; 2108235; 2229064; 2114201National Science Foundation