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Physics posts

• April 25, 2017
• 07:02 AM
• 56 views

The Brightness Temperature of the Quiet Solar Chromosphere at 2.6 mm by Kazumasa Iwai et al

The brightness temperature of the Sun constitutes a basic property of the solar atmosphere. The main emission mechanism of the Sun at millimeter and submillimeter wavelengths is thermal free–free emission from the chromosphere, which is an atmospheric layer with a temperature ranging between 6000 to 20,000 K. The opacity of thermal free–free emission depends on the temperature and density in the emission region. In addition, the Rayleigh– Jeans law is applicable [...]... Read more »

Iwai, K., Shimojo, M., Asayama, S., Minamidani, T., White, S., Bastian, T., & Saito, M. (2017) The Brightness Temperature of the Quiet Solar Chromosphere at 2.6 mm. Solar Physics, 292(1). DOI: 10.1007/s11207-016-1044-5

• April 14, 2017
• 08:58 AM
• 223 views

Well below 1%

When a theory is too hard to solve people try to consider lower dimensional cases. This also happened for Yang-Mills theory. The four dimensional case is notoriously difficult to manage due to the large coupling and the three dimensional case has been treated both theoretically and by lattice computations. In this latter case, the ground […]... Read more »

Andreas Athenodorou, & Michael Teper. (2017) SU(N) gauge theories in 2 1 dimensions: glueball spectra and kstring tensions. J. High Energ. Phys., 15. arXiv: 1609.03873v1

Marco Frasca. (2015) Quantum Yang-Mills field theory. Eur. Phys. J. Plus (2017) 132: 38. arXiv: 1509.05292v2

• April 11, 2017
• 09:00 AM
• 258 views

Looking for clues for past life on Mars

NASA's Curiosity Mars. Credits: NASA/JPL-Caltech/MSSSOn August 6, 2012, the NASA Curiosity rover landed on Mars at the base of Mount Sharp, a mountain the size of Kilimanjaro (~19,000 feet) in the middle of Gale Crater. Nina Lanza, space scientist at the Los Alamos National Laboratory, remembers the day well. As part of the team that built ChemCam, one of the ten instruments on the rover, she spent three months at the Jet Propulsion Laboratory in California, living on “Mars time” to fol........ Read more »

Ricardo, A. (2004) Borate Minerals Stabilize Ribose. Science, 303(5655), 196-196. DOI: 10.1126/science.1092464

Stephenson, J., Hallis, L., Nagashima, K., & Freeland, S. (2013) Boron Enrichment in Martian Clay. PLoS ONE, 8(6). DOI: 10.1371/journal.pone.0064624

• April 11, 2017
• 06:34 AM
• 239 views

How Electron Beams Produce Continuous Coherent Plasma Emission by H. Che, M. Goldstein, P. Diamond, and R. Sagdeev

It is commonly accepted that energetic electron beams can produce drift frequency radio emission or Type III bursts since Ginzburg and Zhelezniakov first proposed the idea in 1958. However, the electron two-stream instability time (see reference 2) in the corona is fraction of a second, while the duration of coronal Type III bursts lasts several orders of magnitude longer. This problem is called the “Sturrock Dilemma” and remains a subject [...]... Read more »

• April 3, 2017
• 09:00 AM
• 196 views

"Science is Under Attack." A Climate Scientist's Call to Action for the Future of our Planet.

It’s a foggy morning in London. Meteorologist George Simpson, the director of the British Meteorological Office, sips his tea and opens a paper authored by a scientist named Guy Stewart Callendar. The last sentence of the abstract reads, “The temperature observations at 200 meteorological stations are used to show that world temperatures have actually increased at an average rate of 0.005°C per year during the past half century.”Simpson shakes his head and thinks, “Nonsense. It’s all ........ Read more »

• March 28, 2017
• 08:04 AM
• 199 views

Radio Diagnostics of Electron Acceleration Sites During the Eruption of a Flux Rope in the Solar Corona by Eoin Carley et al.*

Flares and coronal mass ejections (CMEs) are thought to result from magnetic energy release in the solar corona, often involving the destabilisation of a twisted magnetic structure known as a flux rope (Chen et al. 2011, Webb et al. 2012). This activity may be accompanied by the acceleration of electrons (Kahler 2007, Lin et al. 2011). However, there is ongoing debate on exactly where, when and how this particle acceleration occurs [...]... Read more »

• March 14, 2017
• 08:05 AM
• 248 views

Solar Science with the Atacama Large Millimeter/Submillimeter Array — A New View of Our Sun by S. Wedemeyer

The Atacama Large Millimeter/submillimeter Array (ALMA), which consists of 66 antennas placed on the Chajnantor plateau in the Chilean Andes, has already produced impressive results for a large range of astronomical objects. Regular observations of the Sun have been carried out for the first time in December 2016 and exciting results can be expected soon. ALMA combines high spatial, temporal, and spectral resolution with the diagnostic advantages of radiation at [...]... Read more »

Wedemeyer, S., Bastian, T., Brajša, R., Hudson, H., Fleishman, G., Loukitcheva, M., Fleck, B., Kontar, E., De Pontieu, B., Yagoubov, P.... (2015) Solar Science with the Atacama Large Millimeter/Submillimeter Array—A New View of Our Sun. Space Science Reviews, 200(1-4), 1-73. DOI: 10.1007/s11214-015-0229-9

• March 14, 2017
• 07:08 AM
• 63 views

Nonlinear effects in shallow water waves

I recently googled for something related to the shape of waves and came across a photo of a wave that caught my eye, and it took me to a journey that lead to the article “nonlinear shallow ocean wave soliton interactions on flat beaches” by Ablowitz and Baldwin (2012). What’s discussed in that article is that while…... Read more »

Mark J. Ablowitz, & Douglas E. Baldwin. (2012) Nonlinear shallow ocean wave soliton interactions on flat beaches. Physical Review E, vol. 86(3), pp. 036305 (2012). arXiv: 1208.2904v1

• February 28, 2017
• 07:03 AM
• 218 views

Quasi-periodic acceleration of electrons in the flare on 2012 July 19 by Jing Huang et al.*

We study the quasi-periodic pulsations (QPPs) of nonthermal emission in an M7.7 class flare on 2012 July 19 with spatially resolved observations at microwave and HXR bands and with spectral observations at decimetric, metric waves. Microwave emission at 17 GHz of two footpoints, HXR emission at 20–50 keV of the north footpoint and loop top, and type III bursts at 0.7–3 GHz show prominent in-phase oscillations at 270$\,$s. Through the [...]... Read more »

Huang, J., Kontar, E., Nakariakov, V., & Gao, G. (2016) QUASI-PERIODIC ACCELERATION OF ELECTRONS IN THE FLARE ON 2012 JULY 19. The Astrophysical Journal, 831(2), 119. DOI: 10.3847/0004-637X/831/2/119

• February 24, 2017
• 11:06 AM
• 299 views

What if black holes were not... holes? A Los Alamos physicist explains his alternative theory behind these mysterious objects.

© Elena E. GiorgiThe concept of a “black hole” — a celestial body so dense and massive that not even light can escape its gravitational field — dates back to the 18th century, with the theoretical work of Pierre-Simon Laplace and John Michell. But it wasn’t until the early 20th century that these mysterious dark objects were first described mathematically by German physicist Karl Schwarzschild. Schwarzschild’s work predicted the existence of a finite distance around the black hole (........ Read more »

Mazur, P., & Mottola, E. (2004) Gravitational vacuum condensate stars. Proceedings of the National Academy of Sciences, 101(26), 9545-9550. DOI: 10.1073/pnas.0402717101

Emil Mottola. (2010) New Horizons in Gravity: The Trace Anomaly, Dark Energy and Condensate Stars. Acta Physica Polonica B (2010) Vol.41, iss.9, p.2031-2162. arXiv: 1008.5006v1

• February 20, 2017
• 02:30 PM
• 162 views

This Squid Gives Better Side-Eye Than You

Yes, this cephalopod is looking at you funny. It's a kind of cockeyed squid—an animal that looks like some jokester misassembled a Mr. Potato Head. One of the cockeyed squid's eyes is big, bulging and yellow. The other is flat and beady. After studying more than 25 years' worth of undersea video footage, scientists think they know why.

The Monterey Bay Aquarium Research Institute (MBARI) in California has been dropping robotic submarines into the ocean for decades. The footage from th........ Read more »

• February 14, 2017
• 07:02 AM
• 367 views

Large-scale simulations of Langmuir Wave Distributions Induced by Electron Beams by H. Reid and E. Kontar

Langmuir waves that generate type III radio bursts are excited by high-energy electron beams streaming out from the corona through interplanetary space. Despite a smooth temporal distribution of electrons, the Langmuir waves are measured to occur in discrete clumps, commonly attributed to the turbulent nature of the solar wind electron density (e.g. Smith and Sime 1979, Melrose et al 1986). But how do fluctuations in the background plasma shape the [...]... Read more »

• January 31, 2017
• 07:06 AM
• 580 views

Emission of radiation by plasmas with counter-streaming electron beams by L. F. Ziebell et al.*

The phenomena of emission of radiation by the Sun, which are known as type II and type III solar radio bursts, have been known and investigated for more than sixty years. The bursts of radiation occur at a frequency corresponding to the plasma frequency at the source region, and harmonics [...]... Read more »

Ziebell, L., Petruzzellis, L., Yoon, P., Gaelzer, R., & Pavan, J. (2016) PLASMA EMISSION BY COUNTER-STREAMING ELECTRON BEAMS. The Astrophysical Journal, 818(1), 61. DOI: 10.3847/0004-637X/818/1/61

• January 17, 2017
• 07:03 AM
• 372 views

Simultaneous near-Sun observations of a moving type IV radio burst and the associated white-light CME by K. Hariharan et al.*

Quasi-continuum radio emissions of duration ~10-60 min that occur along with flares and coronal mass ejections (CMEs) in the solar atmosphere are termed as type IV bursts. The bursts are non-thermal in nature and can be classified into two categories, i.e. moving type IV (type IVm) bursts and stationary type [...]... Read more »

• January 3, 2017
• 07:01 AM
• 389 views

Observation of quasi-periodic solar radio bursts associated with propagating fast-mode waves by C. R. Goddard et al.*

Flaring activity on the Sun triggers waves and oscillations in the solar corona. The study of these waves and oscillations allows comparisons to magnetohydrodynamic (MHD) theory and modelling to be made, and seismological inversions based on this comparison allow local plasma parameters to be measured indirectly (e.g. De Moortel & [...]... Read more »

• December 30, 2016
• 12:20 PM
• 388 views

Yang-Mills theory paper gets published!

Exact solutions of quantum field theories are very rare and, normally, refer to toy models and pathological cases. Quite recently, I put on arxiv a pair of papers presenting exact solutions both of the Higgs sector of the Standard Model and the Yang-Mills theory made just of gluons. The former appeared a few month ago […]... Read more »

Marco Frasca. (2015) A theorem on the Higgs sector of the Standard Model. Eur. Phys. J. Plus (2016) 131: 199. arXiv: 1504.02299v3

Marco Frasca. (2015) Quantum Yang-Mills field theory. arXiv. arXiv: 1509.05292v1

Carl M. Bender, Kimball A. Milton, & Van M. Savage. (1999) Solution of Schwinger-Dyson Equations for ${\cal PT}$-Symmetric Quantum Field Theory. Phys.Rev.D62:085001,2000. arXiv: hep-th/9907045v1

• December 27, 2016
• 02:04 PM
• 607 views

Why we have not met Aliens yet?

A huge of number of people keeps on thinking about the existence of some other intelligent beings in the universe but still we have not met any aliens. Why?

Earth is rare

Earth is special planet

One of the reasons that we have not met aliens is that Earth is rare and there is nothing just like Earth in the universe. In this regard, Paleontologist Peter Ward and astronomer Donald Brownlee presented the Rare Earth Hypothesis about 17 years ago.

According to the Rare Earth Hypothesis, t........ Read more »

Heller, R., & Armstrong, J. (2014) Superhabitable Worlds. Astrobiology, 14(1), 50-66. DOI: 10.1089/ast.2013.1088

• December 20, 2016
• 07:02 AM
• 456 views

Diagnosing the Source Region of a Solar Burst on 26 September 2011 by Using Microwave Type-III Pairs by Tan B. L. et al.*

Accelerated electron beams are believed to be responsible for both hard X-ray (HXR) and strong coherent radio emission during solar flares. However, so far the location of the electron acceleration and its physical parameters are poorly known. The solar microwave Type-III pair burst is possibly the most sensitive signature of [...]... Read more »

• December 13, 2016
• 08:23 AM
• 496 views

Acceleration of electrons in the solar wind by Langmuir waves produced by a decay cascade by Catherine Krafft and Alexander Volokitin

It was recently reported that a significant part of the Langmuir waveforms observed by the STEREO satellite (Graham and Cairns, 2013) during type III solar radio bursts are likely consistent with the occurrence of electrostatic decay instabilities, when a Langmuir wave $$\mathcal{L}$$ resonantly interacts with another Langmuir wave $$\mathcal{L}^{\prime}$$ and [...]... Read more »

• December 9, 2016
• 07:18 PM
• 482 views

The Most Interesting Stellar System Of All?

Researchers at the Carnegie Institution of Washington re-examined the Kepler data and determined that it had also been steadily dimming over the course of those four years, on top of its sporadic dips in brightness. For 1,000 days, the rate of dimming observed was constant; then, for 200 days after, its dimming rate suddenly increased by some order of magnitude; finally, for the remaining 200 days, its brightness had remained largely unchanged.... Read more »

Boyajian, T., LaCourse, D., Rappaport, S., & et al. (2016) Planet Hunters IX. KIC 8462852 – where's the flux?. Monthly Notices of the Royal Astronomical Society, 457(4), 3988-4004. DOI: 10.1093/mnras/stw218

Montet, B., & Simon, J. (2016) KIC 8462852 FADED THROUGHOUT THE MISSION . The Astrophysical Journal, 830(2). DOI: 10.3847/2041-8205/830/2/L39