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SUMMARY:Recent advances in the physics of Hall thrusters
DTSTART:20170420T143000
DTEND:20170420T153000
DTSTAMP:20260922T014111Z
UID:9d3112d7c9cdd58acf2e20101f5c7f7b92e733567d3e0a8ff3d2cd21
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. S. Mazouffre\nDirector of research – CNRS\nICARE – Hea
 d of the Electric Propulsion team\nDirector of the scientific task force o
 n Hall thrusters (GIS PPE)\nOrléans\, F\nIn comparison with chemical engi
 nes\, electric propulsion (EP) systems offer significant advantages for co
 mmercial and scientific space missions in terms of payload mass\, launch c
 ost and mission duration due to a fast propellant ejection speed that warr
 ants a large propellant mass saving. For more than two decades\, ion thrus
 ters have been used mainly for north–south station keeping of geosynchro
 nous communication satellites and for space probe journeys towards celesti
 al bodies like asteroids and dwarf planets. With the increase in electrica
 l power available onboard spacecraft\, new possibilities are emerging like
  orbit topping and orbit transfer maneuvers of large satellites\, so makin
 g astronautics fall into the all-electric satellite era. Besides\, progres
 s in the miniaturization of existing EP devices and development of new tec
 hnologies and concepts will open the way for novel applications like micro
 -satellite constellations\, nano-satellite formation flying and active spa
 cecraft end-of-life deorbiting.\n\nAmong all the different EP devices\, tw
 o technologies\, namely the gridded ion engine (GIE) and the Hall thruster
  (HT)\, are at the present time mature with a long flight heritage. GIEs a
 re characterized by a purely electrostatic acceleration of ions\, the latt
 er being extracted from a plasma through a set of high-voltage grids. In c
 ontrast\, HTs are gridless engines. They provide thrust by acceleration of
  ions in a low pressure discharge in a crossed electric and magnetic field
  configuration. GIEs are characterized by a high ion ejection velocity and
  a relatively low thrust level. On the contrary\, HTs provide a relatively
  large thrust with a moderate specific impulse. Due to their large thrust 
 to-power ratio and large thrust density\, Hall thrusters represent an attr
 active electric propulsion technology for satellites maneuvers as well as 
 for several of the foreseen applications for which thrust is a critical pa
 rameter.\n\nDespite 40 years of HT development and investigation\, many ph
 ysical mechanisms that govern the behavior and the performance of such a m
 agnetized discharge are nevertheless ill-understood and not well quantifie
 d. Among others one can cite electron diffusion across the transverse magn
 etic field\, plasma–wall interactions\, plasma instabilities as well as 
 geometrical and size effects. This lack of knowledge is clearly a limiting
  factor for various aspects of the technology: optimization of existing th
 rusters\, derivation of scaling laws\, utilization of alternative propella
 nts and development of new architectures. In this contribution\, I will re
 view some of the advances regarding the physics of the Hall thrusters obta
 ined in the last years through experimental works performed at the ICARE l
 aboratory in Orléans\, France. As we shall see\, results show the possibi
 lity to extend the HT lifetime and to broaden the operating envelope witho
 ut degradation of the performance level. Moreover\, miniaturization of HTs
  down to sizes suitable for micro-spacecraft now appears feasible.
LOCATION:PPB019
STATUS:CONFIRMED
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