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mturmon · 0 points · 0 comments · 6. Aug.

This kind of observation is a big deal for solar physics. It's been believed for decades that these small-scale (~100km and below) turbulent features are critical to understanding how energy dissipates in the Sun. And thus, how sunspots and flares form. The subject has been very qualitative but is yielding on both observational and simulation fronts. I worked adjacent to this area from the 1990s-2010s, and it had been true that MHD numerical simulations of significant volumes of the Sun (but at a scale fine enough to resolve these features) were not possible. That has obviously changed! Additionally, it had been that the best solar observatories could not quite resolve these features. In the late 1990s some of the best images came from a couple of observatories in the Canary Islands (e.g., the 1-meter Swedish telescope -- https://svs.gsfc.nasa.gov/4715/). The spatial resolution was perhaps in the ~100km range. Of course, these are absolutely mind-boggling images. You're looking at a slice of the solar photosphere that has a temperature such that it activates a spectral line around 400nm. By isolating that wavelength, we can see what's happening at that temperature, and thus, sample a slice of the photosphere. So, that had been the state of affairs. Now DKIST (4m aperture), with the particular instrument highlighted in OP, appears to be at a spatial resolution ~5x finer than the above imagery -- see Fig. 1c in the Nature paper (https://www.nature.com/articles/s41586-026-10871-3). It appears also (https://dkist.virtualsolar.org/vanNoortfastcam/) to be observing at 740Hz (!) for speckle reconstructions at ~1Hz. At this scale, vortices of the flow are well-resolved -- where before you just resolved the convective cells but not the turbulent features around them. It's these turbulent features that are transporting energy. To contextualize with respect to a HN perennial topic: DKIST (commissioned 2021) is funded by NSF, from the same pile of money that once funded Arecibo (up to 2020).

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robertlucas6. Aug.

Thanks a lot for sharing your experience with us. I worked adjacent to this area from the 1990s-2010s when the topic is solar physics is definitely why this forum is one of the last "places" of the internet.

BobbyTables27. Aug.

Silly question but how does a 4m aperture focused onto a smaller area not concentrate the heat and melt the instruments?

Zenstvor 6 Tagen

This is not just about the Sun. As we progress towards developing nuclear fusion reactors, a better understanding of the underlying physics may have practical implications for reactor design and could even reveal factors currently being overlooked. At the very least, it will improve modelling. Better models could help fusion reactors retain heat for longer and increase fusion gain (Q), while reducing uncertainty, improving plasma-edge control, and predicting divertor heat loads more accurately.

perpetuallunch7. Aug.

> The subject has been very qualitative What does this mean?