New Jersey Institute of Technology | 2015 Apr 29
[c]Groundbreaking images of the Sun captured by scientists at NJIT’s Big Bear Solar Observatory (BBSO) give a first-ever detailed view of the interior structure of umbrae – the dark patches in the center of sunspots – revealing dynamic magnetic fields responsible for the plumes of plasma that emerge as bright dots interrupting their darkness. Their research is being presented this week at the first Triennial Earth-Sun Summit meeting between the American Astronomical Society’s Solar Physics Division and the American Geophysical Union’s Space Physics and Aeronomy section in Indianapolis, Ind.
A large sunspot observed on Sept 2, 2013 showing umbral flashes and spikes. The
radialy extending thin dark filaments seen against the light orange background are
inflows of plasma into the sunspot. The small streaks of various length visible
inside the sunspot against the dark orange background are the umbral spikes,
which are oscilalting jets driven by sunspot oscillations. [/c]
The high-resolution images, taken through the observatory’s New Solar Telescope (NST), show the atmosphere above the umbrae to be finely structured, consisting of hot plasma intermixed with cool plasma jets as wide as 100 kilometers.
“We would describe these plasma flows as oscillating cool jets piercing the hot atmosphere. Until now, we didn’t know they existed. While we have known for a long time that sunspots oscillate – moderate resolution telescopes show us dark shadows, or penumbral waves, moving across the umbra toward the edge of a sunspot – we can now begin to understand the underlying dynamics,” said Vasyl Yurchyshyn ...
Called spikes, the oscillating jets result from the penetration of magnetic and plasma waves from the Sun’s photosphere – the light-giving layer of its atmosphere – into the abutting chromosphere, which they reach by traveling outward along magnetic tubes that serve as energy conduits. “This process can be likened to a blowhole at a rocky beach, where relentless onshore waves jet sea water high into the air,” Yurchyshyn said. ...
High Resolution Observations of Chromospheric Jets in Sunspot Umbra - V. Yurchyshyn et al
- Astrophysical Journal 787(1) 58 (2014 May 20) DOI: 10.1088/0004-637X/787/1/58
arXiv.org > astro-ph > arXiv:1404.7444 > 29 Apr 2014
- Astrophysical Journal 798(2) 136 (2015Jan 10) DOI: 10.1088/0004-637X/798/2/136
arXiv.org > astro-ph > arXiv:1411.0192 > 02 Nov 2014
New Solar Telescope Peers Deep into the Sun to Track the Origins of Space Weather
New Jersey Institute of Technology | 2015 Apr 28
Witnessing magnetic twist with high-resolution observation from the 1.6-m New Solar Telescope - Haimin Wang et al
- Nature Communications 6 7008 (28 Apr 2015) DOI: 10.1038/ncomms8008