From Lawrence Livermore National Laboratory: “Lab researchers find magnetic fields impact atmospheric circulation of gas giant planets”

From Lawrence Livermore National Laboratory

Aug. 9, 2018
Anne M Stark

This image captures a high-altitude cloud formation surrounded by swirling patterns in the atmosphere of Jupiter’s North North Temperate Belt region. The North North Temperate Belt is one of Jupiter’s many colorful, swirling cloud bands. Scientists have wondered for decades how deep these bands extend. Gravity measurements collected by Juno during its close flybys discovered that these bands of flowing atmosphere actually penetrate deep into the planet, to a depth of about 1,900 miles (3,000 kilometers). Image courtesy of NASA

Magnetic fields around a planet or a star can overpower the zonal jets that affect atmospheric circulation.

New research by a Lawrence Livermore National Laboratory (LLNL) scientist and a collaborator from the Australian National University (ANU) provides a theoretical explanation for why self-organized fluid flows called zonal jets or “zonal flows” can be suppressed by the presence of a magnetic field. The research appears today (Aug. 9) in The Astrophysical Journal.

Zonal flows are observed in the banded zones in the atmosphere of Jupiter. Previous work performed simulations that showed a magnetic field suppressed zonal flows. The new research provides a mechanism explaining that suppression. The study shows that with magnetic fields present, even a weak shear flow causes subtle but coherent correlations in the magnetic fluctuations that oppose zonal flows.

“Because magnetic fields are prevalent in the universe, this theory could be important for understanding dynamics at the solar tachocline where a strong magnetic field exists, and also potentially applicable to zonal flows deep in the interior of Jupiter, Saturn and other gas giants,” said Jeff Parker, LLNL physicist and coauthor of the paper.

Zonal flows are ubiquitous in rotating systems. Prominent examples include the Earth’s polar and subtropical jet streams in the atmosphere, the Antarctic Circumpolar Current in the ocean, the winds in Jupiter’s atmosphere and flows in the atmospheres of Saturn, Uranus and Neptune.

The flows act as a barrier and don’t allow for fluid from the two sides to exchange properties (such as heat or carbon). Thus, zonal flows have a large impact on the Earth’s weather because they separate cold and warm air.

But just how deep do these zonal jets dive in Jupiter? “The zonal flows have an indirect effect on the gravitational field of Jupiter. With detailed measurements of the gravitational field, we can infer how deep the zonal flows are,” said Navid Constantinou, a postdoc at ANU and coauthor of the paper. The recently launched NASA spacecraft Juno is in orbit around Jupiter collecting precisely these sorts of measurements.


Preliminary evidence shows that Jovian winds are as deep as 3,000 kilometers (km). This is still “shallow” when compared to the radius of Jupiter (approximately 70,000 km).

“It has been a long-standing question about how deep zonal flows penetrate into the interior of Jupiter and other gas giants,” Parker said. “Some have argued they exist only on the surface, and others thought they should persist deep into the planet. Only in the last year are we are starting to get answers to these questions, thanks to Juno. It’s an exciting time. Since magnetic fields prevail within Jupiter’s interior, our research could shed light on why the jets don’t go any deeper.”

See the full article here .


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LLNL Campus

Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration
Lawrence Livermore National Laboratory (LLNL) is an American federal research facility in Livermore, California, United States, founded by the University of California, Berkeley in 1952. A Federally Funded Research and Development Center (FFRDC), it is primarily funded by the U.S. Department of Energy (DOE) and managed and operated by Lawrence Livermore National Security, LLC (LLNS), a partnership of the University of California, Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System. In 2012, the laboratory had the synthetic chemical element livermorium named after it.

LLNL is self-described as “a premier research and development institution for science and technology applied to national security.”[1] Its principal responsibility is ensuring the safety, security and reliability of the nation’s nuclear weapons through the application of advanced science, engineering and technology. The Laboratory also applies its special expertise and multidisciplinary capabilities to preventing the proliferation and use of weapons of mass destruction, bolstering homeland security and solving other nationally important problems, including energy and environmental security, basic science and economic competitiveness.

The Laboratory is located on a one-square-mile (2.6 km2) site at the eastern edge of Livermore. It also operates a 7,000 acres (28 km2) remote experimental test site, called Site 300, situated about 15 miles (24 km) southeast of the main lab site. LLNL has an annual budget of about $1.5 billion and a staff of roughly 5,800 employees.

LLNL was established in 1952 as the University of California Radiation Laboratory at Livermore, an offshoot of the existing UC Radiation Laboratory at Berkeley. It was intended to spur innovation and provide competition to the nuclear weapon design laboratory at Los Alamos in New Mexico, home of the Manhattan Project that developed the first atomic weapons. Edward Teller and Ernest Lawrence,[2] director of the Radiation Laboratory at Berkeley, are regarded as the co-founders of the Livermore facility.

The new laboratory was sited at a former naval air station of World War II. It was already home to several UC Radiation Laboratory projects that were too large for its location in the Berkeley Hills above the UC campus, including one of the first experiments in the magnetic approach to confined thermonuclear reactions (i.e. fusion). About half an hour southeast of Berkeley, the Livermore site provided much greater security for classified projects than an urban university campus.

Lawrence tapped 32-year-old Herbert York, a former graduate student of his, to run Livermore. Under York, the Lab had four main programs: Project Sherwood (the magnetic-fusion program), Project Whitney (the weapons-design program), diagnostic weapon experiments (both for the Los Alamos and Livermore laboratories), and a basic physics program. York and the new lab embraced the Lawrence “big science” approach, tackling challenging projects with physicists, chemists, engineers, and computational scientists working together in multidisciplinary teams. Lawrence died in August 1958 and shortly after, the university’s board of regents named both laboratories for him, as the Lawrence Radiation Laboratory.

Historically, the Berkeley and Livermore laboratories have had very close relationships on research projects, business operations, and staff. The Livermore Lab was established initially as a branch of the Berkeley laboratory. The Livermore lab was not officially severed administratively from the Berkeley lab until 1971. To this day, in official planning documents and records, Lawrence Berkeley National Laboratory is designated as Site 100, Lawrence Livermore National Lab as Site 200, and LLNL’s remote test location as Site 300.[3]

The laboratory was renamed Lawrence Livermore Laboratory (LLL) in 1971. On October 1, 2007 LLNS assumed management of LLNL from the University of California, which had exclusively managed and operated the Laboratory since its inception 55 years before. The laboratory was honored in 2012 by having the synthetic chemical element livermorium named after it. The LLNS takeover of the laboratory has been controversial. In May 2013, an Alameda County jury awarded over $2.7 million to five former laboratory employees who were among 430 employees LLNS laid off during 2008.[4] The jury found that LLNS breached a contractual obligation to terminate the employees only for “reasonable cause.”[5] The five plaintiffs also have pending age discrimination claims against LLNS, which will be heard by a different jury in a separate trial.[6] There are 125 co-plaintiffs awaiting trial on similar claims against LLNS.[7] The May 2008 layoff was the first layoff at the laboratory in nearly 40 years.[6]

On March 14, 2011, the City of Livermore officially expanded the city’s boundaries to annex LLNL and move it within the city limits. The unanimous vote by the Livermore city council expanded Livermore’s southeastern boundaries to cover 15 land parcels covering 1,057 acres (4.28 km2) that comprise the LLNL site. The site was formerly an unincorporated area of Alameda County. The LLNL campus continues to be owned by the federal government.


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