Why space dust emits radio waves upon crashing into a spacecraft

May 2, 2017
The high-velocity impact of a piece of dust or orbital debris generates plasma and an associated Radio Frequency emission. Credit: Fletcher/Close

When spacecraft and satellites travel through space they encounter tiny, fast moving particles of space dust and debris. If the particle travels fast enough, its impact appears to create electromagnetic radiation (in the form of radio waves) that can damage or even disable the craft's electronic systems.

A new study published this week in the journal Physics of Plasmas, uses computer simulations to show that the cloud of plasma generated from the particle's impact is responsible for creating the damaging electromagnetic pulse. They show that as the plasma expands into the surrounding vacuum, the ions and electrons travel at different speeds and separate in a way that creates radio frequency emissions.

"For the last few decades researchers have studied these hypervelocity impacts and we've noticed that there's radiation from the impacts when the particles are going sufficiently fast," said lead author Alex Fletcher, now a postdoctoral researcher at the Boston University Center for Space Physics. "No one has really been able to explain why it's there, where it comes from or the physical mechanism behind it."

The study is a step towards verifying the theory of senior author Sigrid Close, associate professor of aeronautics and astronautics at Stanford University. In 2010, Close and colleagues published the initial hypothesis that hypervelocity impact plasmas are responsible for a few satellite failures.

To simulate the results from a hypervelocity impact plasma, researchers used a method called particle-in-cell simulation that allows them to model the plasma and the electromagnetic fields simultaneously. They fed the simulation details from a previously developed hydrocode—a computational tool they used to model the fluid and solid dynamics of the impact. The researchers let the simulation evolve and calculated the radiation produced by the plasma.

When a particle hits a hard surface at high speeds, it vaporizes and ionizes the target, releasing a cloud of dust, gas and plasma. As the plasma expands into the surrounding vacuum (of space), its density drops and it enters a collisionless state where its particles no longer interact directly with one another.

In the current study, the researchers make the assumption that the electrons in this collisionless plasma then travel faster than the larger ions. Their simulation predicts that this large-scale charge separation generates the radiation. The model's results are consistent with Close's initial theory, but predict a higher frequency for the emission than researchers have detected experimentally.

The authors point out that the assumption that the electrons move en masse as they separate from the ions deserves more careful attention. The group is building new simulations to test whether the shift to a collisionless state is sufficient to create the separation.

Fletcher also notes that they have neglected to account for the dust.

"The creates dust that interact with the ," Fletcher said. The dynamics of these "dusty plasmas" are an area for future research.

The next step in the work is to use the to quantify the radiation generated so they can assess the threat to satellites, and devise ways to protect satellites and spacecraft from meteoroids and orbital debris.

"More than half of electrical failures are unexplained because it's very hard to do diagnostics on a satellite that fails in orbit," Fletcher said. "We believe we can attribute some of these failures to this mechanism."

Explore further: Japanese researchers find new classes of electron orbits

More information: "Particle-in-cell simulations of an RF emission mechanism associated with hypervelocity impact plasmas," Physics of Plasmas, May 2, 2017. DOI: 10.1063/1.4980833

Related Stories

Japanese researchers find new classes of electron orbits

October 5, 2016

Phenomena like solar flares and auroras are consequences of magnetic reconnection in the near-Earth space. These "magnetic reconnection" events are akin to magnetic explosions that accelerate particles as they rapidly change ...

Reading between the lines of highly turbulent plasmas

March 29, 2017

Plasma, the ionised state of matter found in stars, is still not fully understood, largely due to its instability. Astrophysicists have long sought to develop models that can account for the turbulent motions inside plasma, ...

Ripples in space key to understanding cosmic rays

October 17, 2016

In a new study researchers at the Swedish Institute of Space Physics have used measurements from NASA's MMS (Magnetospheric MultiScale) satellites to reveal that there are ripples, or surface waves, moving along the surface ...

Clarifying plasma oscillation by high-energy particles

November 29, 2016

The National Institute for Fusion Science has developed new code that can simulate the movement of plasma and, simultaneously, the movement of particles circulating at high speeds. In the Japanese fusion reactor called the ...

Calculating one billion plasma particles in a supercomputer

December 21, 2016

At the National Institutes of Natural Sciences National Institute for Fusion Science (NIFS) a research group using the NIFS 'Plasma Simulator' supercomputer succeeded for the first time in the world in calculating the movements ...

Recommended for you

Single-photon detector can count to four

December 15, 2017

Engineers have shown that a widely used method of detecting single photons can also count the presence of at least four photons at a time. The researchers say this discovery will unlock new capabilities in physics labs working ...

Real-time observation of collective quantum modes

December 15, 2017

A cylindrical rod is rotationally symmetric - after any arbitrary rotation around its axis it always looks the same. If an increasingly large force is applied to it in the longitudinal direction, however, it will eventually ...

A shoe-box-sized chemical detector

December 15, 2017

A chemical sensor prototype developed at the University of Michigan will be able to detect "single-fingerprint quantities" of substances from a distance of more than 100 feet away, and its developers are working to shrink ...

An ultradilute quantum liquid made from ultra-cold atoms

December 14, 2017

ICFO researchers created a novel type of liquid 100 million times more dilute than water and 1 million times thinner than air. The experiments, published in Science, exploit a fascinating quantum effect to produce droplets ...

4 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

HannesAlfven
1 / 5 (5) May 02, 2017
Re: "They show that as the plasma expands into the surrounding vacuum, the ions and electrons travel at different speeds"

Yes, and this has also been used to explain how charge separation can occur in space plasmas.
691Boat
5 / 5 (10) May 02, 2017
Re: "They show that as the plasma expands into the surrounding vacuum, the ions and electrons travel at different speeds"

Yes, and this has also been used to explain how charge separation can occur in space plasmas.


But in this article it is only being applied during the formation of said plasma, working against a "solid" surface directly following impact. explain your comment a bit more if you can.
-What generates the plasma?
-What is the plasma acting against to accelerate the ions and electrons?
thanks!
nikola_milovic_378
May 03, 2017
This comment has been removed by a moderator.
Captain Stumpy
5 / 5 (2) May 03, 2017
All of matter and energy in the universe formed from the ether that fills the infinite universe
https://www.natur...omms9174

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.