Scientists Report First-Ever 3-D Observations of Solar Storms

New Jersey Institute of Technology/Bell Labs physicist Louis Lanzerotti
was participated in international team that studied the unquiet sun when
it was most active and found interesting phenomena

Newark, NJ-The sun’s surface is a violent and turbulent place, where
a fiery tempest always blows. Scientists are reporting in the journal
Science today that they have finally succeeded in getting a good
three-dimensional view of it.

“The sun is huffing and puffing and blowing off steam,” said Louis
Lanzerotti, a member of an international team that used the Ulysses
spacecraft to make the first-ever 3-D study of our parent star during
solar maximum, the peak of the sun’s 11-year activity cycle. “Ulysses
gave us a chance to observe the sun from unique vantage points to
better understand solar storms and their consequences.”

Scientists have been trying to understand solar weather for years, in
an effort to better predict terrestrial consequences of solar storms.
Solar storms sometimes severely disrupt wireless telephone calls,
satellite communications and electric power grids on Earth.

Ulysses, launched in 1990 by the shuttle Discovery as a joint mission
of NASA and the European Space Agency, has an orbit that takes it
over the solar poles, giving scientists a chance to look at the sun
from all angles.

“No other spacecraft can do that,” said Lanzerotti, a solar physicist
who divides his time between Lucent Technologies’ Bell Labs, which he
joined in 1965 and where he is now a consultant, and the New Jersey
Institute of Technology, where he is a distinguished research
professor at the Center for Solar Terrestrial Research. “Many space
missions have observed the sun near its equator, but only Ulysses has
traveled from the solar equator to above the sun’s polar caps.”

Ulysses began its first solar orbit in 1992 and completed it in 1998,
a period when solar activity was at a minimum. But during the second
orbit, begun in 1998, the sun was at its most turbulent.

The scientists report that, during this period, huge explosions on
the sun hurled vast amounts of solar material into space. Called
coronal mass ejections, since the sun’s outermost layer — the corona
— throws them off, these swirling, boiling plumes travel out from
the sun and are thought to be caused by the severest of solar gales.

“We just had a coronal mass ejection last week,” Lanzerotti noted.
“These are some of the most violent phenomena associated with the
sun. We were able to look at a few that happened around the recent
solar maximum.”

The team also got to observe the solar wind – the stream of charged
particles that are emitted by the sun. The solar wind blows out a
giant bubble called the heliosphere within the interstellar medium,
the dilute gas and dust that fills the space between stars. The sun’s
influence extends far beyond the orbits of the outer planets and the
vast reservoir of periodic comets known as the Kuiper Belt because
the solar wind fills the heliosphere and exerts an outward pressure
on the interstellar medium. (The boundary between the heliosphere and
the interstellar medium is the true edge of the solar system, a place
where a lot of interesting physical phenomena take place. Last week,
a separate team of scientists, of which Lanzerotti is also a member,
reported in the journal Nature that Voyager 1 has reached the edge of
the solar system.)

Data from Ulysses show that the solar wind originates in holes in the
sun’s corona, and the speed of the solar wind varies inversely with
coronal temperature.

“This was completely unexpected,” said Lanzerotti. “Theorists had
predicted the opposite. Now all models of the sun and the solar wind
will have to explain this observation.”

Another surprising finding based on Ulysses’ data is that the sun’s
magnetic field originates from a magnet that seems to be
perpendicular to the sun’s axis of rotation (instead of being parallel
to it, as is the case with Earth).

“At solar maximum, the sun’s polar cap magnetic fields reverse
direction or sign,” said Edward Smith of NASA’s Jet Propulsion Lab at
the California Institute of Technology, who is the US project
scientist for the Ulysses mission. “Inward fields become outward and
vice versa. Ulysses observations show that during this reversal, the
Sun’s magnetic poles are located near the solar equator instead of in
the polar caps.”

The sun has a powerful magnetic field — the needle of a compass
placed on the sun’s surface would be deflected so strongly that it
would require Herculean strength to push it back. It is thought that
solar activity is strongly related to changes in the sun’s magnetic
field.

“We knew that the sun’s magnetic field was dynamic and variable,”
said Lanzerotti. “But this shows that we still have a lot of
understanding to do. No one really knows how it is formed and why it
changes as it does.”

Other members of the scientific team were: R.G. Marsden (European
project scientist) and M. Landgraf of the European Space Agency in
the Netherlands; A. Balogh of Imperial College, London; G.
Gloeckler of the University of Maryland; J. Geiss of the
International Space Science Institute in Switzerland; D. J. McComas
of Southwest Research Institute; R.B. McKibben of the University of
New Hampshire; R. J. MacDowall of NASA Goddard Space Flight Center;
and N. Krupp and H. Krueger of the Max Planck Institutes in Germany.

The team’s paper, “The Sun and Heliosphere at Solar Maximum,”
appears in the November 14, 2003 issue of Science on page 1165.

About NJIT

NJIT, located in Newark, New Jersey, is a public, scientific and
technological research university enrolling more than 8,800
students. The university offers bachelor’s, master’s and doctoral
degrees to students in 80 degree programs throughout its six
colleges: Newark College of Engineering, New Jersey School of
Architecture, College of Science and Liberal Arts, School of
Management, Albert Dorman Honors College and College of Computing
Sciences. The division of continuing professional education
offers adults eLearning, off campus degrees and short courses.
Expertise and research initiatives include architecture and
building science, applied mathematics, biomedical engineering,
environmental engineering and science, information technology,
manufacturing, materials, microelectronics, multimedia,
telecommunications, transportation and solar astrophysics. NJIT
ranks in the top tier of U.S. News & World Report’s list of
national doctoral universities.

About Lucent Technologies’ Bell Labs

Bell Labs is the leading source of new communications technologies.
It has generated more than 30,000 patents since 1925 and has played
a pivotal role in inventing or perfecting key communications
technologies, including transistors, digital networking and signal
processing, lasers and fiber-optic communications systems,
communications satellites, cellular telephony, electronic switching
of calls, touch-tone dialing, and modems. Bell Labs scientists
have received six Nobel Prizes in Physics, nine U.S. National
Medals of Science and eight U.S. National Medals of Technology. For
more information about Bell Labs, visit its Web site at
http://www.bell-labs.com.

Lucent Technologies (NYSE: LU), headquartered in Murray Hill, N.J.,
USA, designs and delivers networks for the world’s largest
communications service providers. Backed by Bell Labs research and
development, Lucent relies on its strengths in mobility, optical,
data and voice networking technologies as well as software and
services to develop next-generation networks. The company’s systems,
services and software are designed to help customers quickly deploy
and better manage their networks and create new, revenue-generating
services that help businesses and consumers. For more information
on Lucent Technologies, visit its Web site at http://www.lucent.com.