Nav: Home

Neptune: Neutralizer-free plasma propulsion

May 23, 2017

WASHINGTON, D.C., May 23, 2017 -- Plasma propulsion is an important and efficient technology used to control spacecraft for Earth observation, communications and fundamental exploration of outer space.

Plasma propulsion systems use electric power to ionize propellant gas and transform it into the fourth state of matter, known as plasma. Electrically charged ions and electrons are accelerated in an exhaust beam to generate thrust and propel the spacecraft.

The most established electric propulsion concepts, for example gridded-ion thrusters, accelerate and emit a larger number of positively charged particles than those with negative charge. To enable the spacecraft to remain charge-neutral, a "neutralizer" is used to inject electrons to exactly balance the positive ion charge in the exhaust beam. However, the neutralizer requires additional power from the spacecraft and increases the size and weight of the propulsion system.

A team from the University of York and École Polytechnique is investigating how the neutralizer can be removed altogether. The researchers report their findings this week in the journal Physics of Plasmas, from AIP Publishing.

In 2014, Dmytro Rafalskyi and Ane Aanesland from the Laboratory of Plasma Physics, École Polytechnique, France demonstrated a new electric propulsion concept. The concept, called Neptune, leverages the technological heritage of gridded-ion thrusters. However, as comparable numbers of positively and negatively charged particles are present in the exhaust beam the neutralizer is no longer needed.

To further develop the Neptune concept towards spaceflight, the researchers were interested in understanding how the plasma interacts with the acceleration system so that a charge-neutral beam is generated. They teamed up with James Dedrick and Andrew Gibson from the York Plasma Institute, University of York, U.K. to study how plasma behavior varies in relation to spatial location, time and particle energy.

"The direct observation of how energetic plasma species behave on nanosecond timescales in the Neptune beam will help us to better control the processes that underpin neutralization," Dedrick said.

As part of their investigation, the researchers studied the dynamics of negatively charged energetic electrons in the exhaust beam of the thruster and their behavior was observed to play a key role in beam neutralization.

"We believe that this arises from a complex interaction between the plasma and acceleration grids, which is highly dependent upon the particle dynamics nearby to the grid surface," Dedrick said.
-end-
The article, "Transient propagation dynamics of owing plasmas accelerated by radio-frequency electric fields," is authored by James Dedrick, Andrew Gibson, Dmytro Rafalskyi and Ane Aanesland. The article will appear in the journal Physics of Plasmas May 23, 2017 [DOI: 10.1063/1.4983059]. After that date, it can be accessed at http://aip.scitation.org/doi/full/10.1063/1.4983059.

ABOUT THE JOURNAL

Physics of Plasmas is devoted to the publication of original experimental and theoretical work in plasma physics, from basic plasma phenomena to astrophysical and dusty plasmas. See http://pop.aip.org.

American Institute of Physics

Related Plasma Articles:

Plasma-driven biocatalysis
Compared with traditional chemical methods, enzyme catalysis has numerous advantages.
How bacteria protect themselves from plasma treatment
Considering the ever-growing percentage of bacteria that are resistant to antibiotics, interest in medical use of plasma is increasing.
A breakthrough in the study of laser/plasma interactions
Researchers from Lawrence Berkeley National Laboratory and CEA Saclay have developed a particle-in-cell simulation tool that is enabling cutting-edge simulations of laser/plasma coupling mechanisms.
Researchers turn liquid metal into a plasma
For the first time, researchers at the University of Rochester's Laboratory for Laser Energetics (LLE) have found a way to turn a liquid metal into a plasma and to observe the temperature where a liquid under high-density conditions crosses over to a plasma state.
How black holes power plasma jets
Cosmic robbery powers the jets streaming from a black hole, new simulations reveal.
Give it the plasma treatment: strong adhesion without adhesives
A Japanese research team at Osaka University used plasma treatment to make fluoropolymers and silicone resin adhere without any adhesives.
Chemotherapeutic drugs and plasma proteins: Exploring new dimensions
This review provides a bird's eye view of interaction of a number of clinically important drugs currently in use that show covalent or non-covalent interaction with serum proteins.
The coming of age of plasma physics
The story of the generation of physicists involved in the development of a sustainable energy source, controlled fusion, using a method called magnetic confinement.
Intense microwave pulse ionizes its own channel through plasma
More than 30 years ago, researchers theoretically predicted the ionization-induced channeling of an intense microwave beam propagating through a neutral gas (>103 Pa) -- and now it's finally been observed experimentally.
Plasma thruster: New space debris removal technology
A Japanese and Australian research group has discovered new technology to remove space debris using a single propulsion system in a helicon plasma thruster.
More Plasma News and Plasma Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.