Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The Protecting Cocoon of the Solar System: NASA Mission discovers unexpected structures

16.10.2009
RUB astrophysicist with two publications in Science

The solar wind engulves our solar system like a cocoon: This continuous plasma flow that emanates from the Sun is protecting us from the interstellar medium, especially from the cosmic rays. The boundary of this cocoon is a long-standing topic of space research.

Now the NASA spacecraft IBEX (Interstellar Boundary Explorer) has, for the first time, detected energetic hydrogen atoms from this region resulting in a surprise: The measurements indicate entirely unexpected structures in the flux of these particles.

"All scientists have, so far, modelled this outer boundary without an interstellar magnetic field - nobody has expected its strong influence", states PD Dr. Horst Fichtner (Institut für Theoretische Physik IV der RUB). He and his international colleagues present these observations and new improved models of this cocoon in two publications in Science.

Electron exchange at the boundary of the heliosphere

The IBEX spacecraft, launched in October last year into Earth orbit, has pointed its novel detectors away from Earth into outer space and records how many energetic hydrogen atoms arrive per time interval from a given direction. Step by step it has scanned the whole sky and provided the first all-sky map of this particle flux, which allows to infer the physical conditions at the outer boundary of our solar system: At the outer edge of the heliosphere - the plasma cocoon - the solar wind plasma interacts with the interstellar medium. The solar wind consists partly of fast protons, the interstellar medium to a large fraction of slow hydrogen atoms. There is a specific probability that close encounters result in a transfer of an electron from the slow hydrogen atom to the fast proton. "Thereby, the two particles exchange their roles", explains Dr. Fichtner, "the fast proton transforms into a fast hydrogen atom and vice versa. We can measure the result of this transformation."

Modelling without the interstellar magnetic field

The all-sky map measured by IBEX surprised the scientists, however. It showed only partly the theoretically predicted structures, which were obtained under the assumption that the flux of energetic atoms is mainly determined by the solar wind and not by the interstellar magnetic field. Instead an intensity ribbon - resulting from relatively many exchange processes - showed up that stretches "diagonally" across the all-sky map. "Meanwhile, we know why", explains Horst Fichtner. "This ribbon fits to the interstellar magnetic field. The latter has been neglected in the models so far."

New scenarios

In the second Science publication the researchers now develop scenarios to explain the newly observed data. "We assume that the magnetic field plays a dynamic role leading to a compression of the heliosphere at its boundary", says Fichtner. The magnetic field forces the plasma flow from the Sun to decelerate resulting in an accumulation of particles. Thereby, the probability for "collisions" and, hence, that for electron transfer increase.

Waiting for further measurements

"These first results of the IBEX mission are a milestone on the way to a deeper understanding of the heliosphere and its galactic environment, which also determines the conditions for life on Earth.", comments Horst Fichtner, who heads a heliospheric research group. The detailed insights into the physics of the heliosphere can be transferred to other stars and help to understand the significance of astrospheres for extrasolar planets. The IBEX observations also show first indications for a time variability of the flux of neutral atoms and, thus, of the structure of the heliosphere: "Based on our models this is what we expect as a consequence of solar activity cycle", says Dr. Fichtner. The confirmation of such variation can, however, only result from measurements over a longer period. "The further measurements by IBEX, which will be operating for at least two years but, probably, far more, are eagerly expected!"

IBEX

IBEX is the latest in NASA's series of low-cost, rapidly developed Small Explorers space missions. Southwest Research Institute in San Antonio, TX, leads and developed the mission with a team of national and international partners. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the Explorers Program for NASA's Science Mission Directorate in Washington.

Titles

N. A. Schwadron, M. Bzowski, G. B. Crew, M. Gruntman, H. Fahr, H. Fichtner, P. C. Frisch, H. O. Funsten, S. Fuselier, J. Heerikhuisen, V. Izmodenov, H. Kucharek, M. Lee, G. Livadiotis, D. J. McComas, E. Moebius, T. Moore, J. Mukherjee, N. V. Pogorelov, C. Prested, D. Reisenfeld, E. Roelof, and G. P. Zank: Comparison of Interstellar Boundary Explorer Observations with 3-D Global Heliospheric Models. In: Science Express, Published online October 15 2009; 10.1126/science.1180986 (Science Express Reports)

D. J. McComas, F. Allegrini, P. Bochsler, M. Bzowski, E. R. Christian, G. B. Crew, R. DeMajistre, H. Fahr, H. Fichtner, P. C. Frisch, H. O. Funsten, S. A. Fuselier, G. Gloeckler, M. Gruntman, J. Heerikhuisen, V. Izmodenov, P. Janzen, P. Knappenberger, S. Krimigis, H. Kucharek, M. Lee, G. Livadiotis, S. Livi, R. J. MacDowall, D. Mitchell, E. Mobius, T. Moore, N. V. Pogorelov, D. Reisenfeld, E. Roelof, L. Saul, N. A. Schwadron, P. W. Valek, R. Vanderspek, P. Wurz, and G. P. Zank: Global Observations of the Interstellar Interaction from the Interstellar Boundary Explorer (IBEX), In: Science Express, Published online October 15 2009; DOI: 10.1126/science.1180906 (Science Express Reports)

Further Information

PD Dr. Horst Fichtner, Institut für Theoretische Physik der Ruhr-Universität, 44780 Bochum, Tel. 0234/32-23786, E-Mail: hf@tp4.rub.de

Dr. Josef König | idw
Further information:
http://ibex.swri.edu/
http://www.pm.ruhr-uni-bochum.de/pm2009/msg00229.htm

More articles from Physics and Astronomy:

nachricht Significantly more productivity in USP lasers
06.12.2016 | Fraunhofer-Institut für Lasertechnik ILT

nachricht Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore

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: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Predicting unpredictability: Information theory offers new way to read ice cores

07.12.2016 | Earth Sciences

Sea ice hit record lows in November

07.12.2016 | Earth Sciences

New material could lead to erasable and rewriteable optical chips

07.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>