Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Table top plasma gets wind of solar turbulence

30.06.2017

Turbulent magnetic field dynamics that explain astrophysical phenomena like the evolution of stars could thus far be obtained only through observations via telescopes and satellites. Now a team of scientists from India and Portugal have recreated such magnetic turbulence on a table top in the lab, using a high intensity ultrashort laser pulse to excite a hot, dense plasma on a solid surface and followed the extremely fast evolution of the giant magnetic field generated by the plasma dynamics. This ground-breaking study will be published in Nature Communications on 30 June.

Turbulence is everywhere- from tea cups to tokomaks and from water jets to weather systems, it is something we all see and experience. Yet, even after centuries of serious scientific study, fluid turbulence is still not properly understood and remains "Interesting. Vexing. Longstanding. Unsolved."[1]. While it is difficult to define turbulence simply, it has many recognizable features, the most common being the fluctuations in parameters like velocity and pressure, indicating randomization of the flow [2].


(a) A pump pulse creates the plasma on a solid while a probe pulse monitors the time evolution. The top panel in b shows the spatially randomized magnetic field in the plasma while the figure at the bottom shows the power spectrum of the magnetic field (magnetic energy density variation of with inverse of spatial length. The curve indicates magnetic turbulence in the plasma and mimics that from the solar wind.

Credit: G. Chatterjee et al., Nature Communications, 10.1038/NCOMMS15970

By the way, turbulence is not all bad and destructive as you might feel when tossed around on a flight during bad weather. One good feature is that it enables much faster mixing than possible only with normal, slow diffusion. For instance, the sugar you added in your cup of tea this morning would have taken hours and days to disperse but for your stirring which caused your tea to become turbulent.

As you have surely noticed, you stirred the tea in a large circle, but the swirling spread to smaller and smaller lengths and eventually, the mixing occurred at the molecular level. The end result? Even the smallest drop of tea is as sweet as a large gulp! Turbulence also helps in mixing fuel and oxygen for efficient combustion in engines.

Much of our universe is of course not an ordinary fluid but consists of highly ionized gas known as plasma and this plasma can often be extremely hot and swirling at unimaginable speeds. Turbulence in a plasma is much more complex than that in neutral hydrodynamic fluids.

In a charged plasma environment, the negatively charged, light electrons and positive heavy ions respond at vastly different length and time scales. The motion of these charged species is governed by electromagnetic forces and the current flow through the charge particle dynamics leads to magnetic field generation. Therefore the randomness of magnetic fields often mimics the fluid turbulence in plasmas.

The team of scientists leading this new study, at the Tata Institute of Fundamental Research, Mumbai, Institute of Plasma Research, Gandhinagar (both in India) and at the Instituto Superior Tecnico, Universidade de Lisboa, Portugal find that the turbulence in the magnetic field is initially driven by the electrons (at a trillionth of a second) and the ions step in and take over at longer times.

This is the first time such a 'relay race' involving two different species has been glimpsed. Further, these lab observations have an uncanny resemblance to the satellite data on the magnetic field spectra measured for turbulent astrophysical plasmas in the solar wind, solar photosphere and earth's magnetosheath. Although in the laser experiment the electrons in the plasma get energised initially, the ion dominant response that kicks in at later times shows spectral features similar to those in the astro systems.

These experiments thus establish clear connections between the two scenarios, even though the driver of turbulence in the lab plasma is very different from that in the astrophysical system.

Now that we have got wind of solar turbulence on a table top, can we use lab experiments to turn the tables on the intractable problem of turbulence? Well, that may still be a long way off but it is a tantalising prospect that reliable measurements in the lab might make us better and better at peeking into turbulent stellar scenarios.

And that should set off stars in our eyes!

###

References:

[1] L.P. Kadanoff, Physics Today, Vol. 48, no.9, p11 (1995)
[2] K.R. Sreenivasan, McGraw-Hill Encyclopaedia of Science and Technology, 10th Edn., Vol. 18, p725.
[3] G. Chatterjee et al., Nature Communications, 10.1038/NCOMMS15970 (2017)

Media Contact

G. Ravindra Kumar
grk@tifr.res.in
91-998-773-7422

http://www.tifr.res.in 

G. Ravindra Kumar | EurekAlert!

More articles from Physics and Astronomy:

nachricht APEX takes a glimpse into the heart of darkness
25.05.2018 | Max-Planck-Institut für Radioastronomie

nachricht First chip-scale broadband optical system that can sense molecules in the mid-IR
24.05.2018 | Columbia University School of Engineering and Applied Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>