151,960 research outputs found
On the Nature and Genesis of EUV Waves: A Synthesis of Observations from SOHO, STEREO, SDO, and Hinode
A major, albeit serendipitous, discovery of the SOlar and Heliospheric
Observatory mission was the observation by the Extreme Ultraviolet Telescope
(EIT) of large-scale Extreme Ultraviolet (EUV) intensity fronts propagating
over a significant fraction of the Sun's surface. These so-called EIT or EUV
waves are associated with eruptive phenomena and have been studied intensely.
However, their wave nature has been challenged by non-wave (or pseudo-wave)
interpretations and the subject remains under debate. A string of recent solar
missions has provided a wealth of detailed EUV observations of these waves
bringing us closer to resolving their nature. With this review, we gather the
current state-of-art knowledge in the field and synthesize it into a picture of
an EUV wave driven by the lateral expansion of the CME. This picture can
account for both wave and pseudo-wave interpretations of the observations, thus
resolving the controversy over the nature of EUV waves to a large degree but
not completely. We close with a discussion of several remaining open questions
in the field of EUV waves research.Comment: Solar Physics, Special Issue "The Sun in 360",2012, accepted for
publicatio
Interacting with Acoustic Simulation and Fabrication
Incorporating accurate physics-based simulation into interactive design tools
is challenging. However, adding the physics accurately becomes crucial to
several emerging technologies. For example, in virtual/augmented reality
(VR/AR) videos, the faithful reproduction of surrounding audios is required to
bring the immersion to the next level. Similarly, as personal fabrication is
made possible with accessible 3D printers, more intuitive tools that respect
the physical constraints can help artists to prototype designs. One main hurdle
is the sheer amount of computation complexity to accurately reproduce the
real-world phenomena through physics-based simulation. In my thesis research, I
develop interactive tools that implement efficient physics-based simulation
algorithms for automatic optimization and intuitive user interaction.Comment: ACM UIST 2017 Doctoral Symposiu
Best Approximation to a Reversible Process in Black-Hole Physics and the Area Spectrum of Spherical Black Holes
The assimilation of a quantum (finite size) particle by a
Reissner-Nordstr\"om black hole inevitably involves an increase in the
black-hole surface area. It is shown that this increase can be minimized if one
considers the capture of the lightest charged particle in nature. The
unavoidable area increase is attributed to two physical reasons: the Heisenberg
quantum uncertainty principle and a Schwinger-type charge emission (vacuum
polarization). The fundamental lower bound on the area increase is ,
which is smaller than the value given by Bekenstein for neutral particles.
Thus, this process is a better approximation to a reversible process in
black-hole physics. The universality of the minimal area increase is a further
evidence in favor of a uniformly spaced area spectrum for spherical quantum
black holes. Moreover, this universal value is in excellent agreement with the
area spacing predicted by Mukhanov and Bekenstein and independently by Hod.Comment: 10 page
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