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International Affairs Students Current Students Alumni Faculty/Staff Careers--> TOHOKU UNIVERSITYCREATING GLOBAL EXCELLENCE Search 日本語 Contact Tohoku University --> About Facts & Figures Facilities Organization Chart History President's Message Top Global University Project Designated National University Global Network Promotional Videos Academics Undergraduate Graduate Courses in English Exchange Programs Summer Programs Double Degree Programs Academic Calendar Syllabus Admissions Undergraduate Admissions Graduate Admissions Fees and Expenses Financial Aid Research Feature Highlights Research Releases University Research News Research Institutes Visitor Research Center Research Profiles Academic Research Staff Campus Life International Support Office IT Services Facilities Dining & Shops Campus Bus Clubs & Circles News University News Research--> Arts & Culture Health & Sports Campus & Community Press Release--> International Visit Alumni Careers Events Exhibits Music Special Event Lecture Alumni--> Map & Directions Campus Maps & Bus--> Facilities Map--> TOHOKUUNIVERSITY About Academics Admissions Research Campus Life News Events International Affairs Students Current Students Alumni Faculty/Staff Promotional Videos Subscribe to our Newsletter Map & Directions Contact Jobs & Vacancies Emergency Information Site Map 日本語 Close Home Research News Can Plasma Instability In Fact Be the Savior for Magnetic Nozzle Plasma Thrusters Research News Can Plasma Instability In Fact Be the Savior for Magnetic Nozzle Plasma Thrusters 2022-12-06 A research group has demonstrated that spontaneously excited plasma waves may be the solution to a long-associated problem with magnetic nozzle plasma thrusters, turning conventional thinking on its head. Details of their research were published in the journal Scientific Reports on December 5, 2022. In magnetic nozzle radio frequency thrusters, sometimes referred to as helicon thrusters, magnetic nozzles channel and accelerate plasma to allow spacecraft to generate thrust. The technology, which harnesses electric propulsion, shows great potential for ushering in a new era of space travel. Yet the so-called "plasma detachment" problem has hampered further development. Since magnetic field lines always form closed loops, the ones inside magnetic nozzles inevitably turn back to the thruster structure. For this reason, the plasma flow has to be detached from the magnetic nozzle. Ions, having a large gyro radius, detach easily from the magnetic nozzle. But electrons, with their small mass and small gyro radius, are tied to the field lines, generating an electric field that pulls the ions back and renders a net thrust of zero. An image of the cross-field electron transport and plasma detachment from the magnetic nozzle. ©Kazunori Takahashi When plasma expands, it can gain or lose energy and momentum due to waves, turbulence or electromagnetic forces. Plasma transport and loss due to the wave and turbulence have been a major issue for confining plasma in thermonuclear fusion reactors. Yet after analyzing the detailed data from the plasma density and electric field fluctuation signals, the research group from Tohoku University and The Australian National University discovered that the spontaneously excited waves brought about an inward cross-field transport of magnetized electrons towards the main axis of the magnetic nozzle, neutralizing the ions detaching. The electron inward transport was in fact beneficial to detachment, helping to reduce the divergence of the expanding plasma beam. "Our discovery is a rare case where plasma instabilities actually have a favorable effect on engineering," said Professor Kazunori Takahashi, from Tohoku University's Department of Electrical Engineering, and lead author of the study. "Our findings open up a new perspective on the role of instabilities in plasmas, and will help the development of magnetic nozzle radio frequency plasma thrusters." A brief description of the magnetic nozzle plasma thruster. The upper-left inset is a photo of the thruster operating in a laboratory. ©Kazunori Takahashi Publication Details: Title: Wave-driven electron inward transport in a magnetic nozzleAuthors: Kazunori Takahashi, Christine Charles, and Rod W. BoswellJournal: Scientific ReportsDOI: 10.1038/s41598-022-24202-9 Press release in Japanese Contact: Kazunori Takahashi (Profile)Email: kazunori.takahashi.e8tohoku.ac.jp Archives 2014&＃24180; 2015&＃24180; 2016&＃24180; 2017&＃24180; 2018&＃24180; 2019&＃24180; 2020&＃24180; 2021&＃24180; 2022&＃24180; 2023&＃24180; Page Top About Tohoku University Academics Admissions Research Campus Life News Events International Affairs Students Alumni Promotional Videos Subscribe to our Newsletter Map & Directions Contact Tohoku University Jobs & Vacancies Emergency Information Site Map Media Enquiries Parent & Family Support Public Facilities Contact Tohoku University