Editing Hall-effect thruster (section)

====Cylindrical Hall thrusters====
[[File:Hall Effect Thruster in a vacuum chamber.jpg|thumb|An Exotrail ExoMG – nano (60&nbsp;W) Hall Effect Thruster firing in a vacuum chamber]]

Although conventional (annular) Hall thrusters are efficient in the [[kilowatt]] power regime, they become inefficient when scaled to small sizes. This is due to the difficulties associated with holding the performance scaling parameters constant while decreasing the channel size and increasing the applied [[magnetic field]] strength. This led to the design of the cylindrical Hall thruster. The cylindrical Hall thruster can be more readily scaled to smaller sizes due to its nonconventional discharge-chamber geometry and associated [[magnetic field]] profile.<ref>{{cite web|first1=Y. |last1=Raitses |first2=N. J. |last2=Fisch |title=Parametric Investigations of a Nonconventional Hall Thruster|url=http://htx.pppl.gov/publication/Journal/CHT_PoP_2001.pdf|publisher=Physics of Plasmas, 8, 2579 (2001)|url-status=live|archive-url=https://web.archive.org/web/20100527094903/http://htx.pppl.gov/publication/Journal/CHT_PoP_2001.pdf|archive-date=27 May 2010}}</ref><ref>{{cite web|first1=A. |last1=Smirnov |first2=Y. |last2=Raitses |first3=N. J. |last3=Fisch |title=Experimental and theoretical studies of cylindrical Hall thrusters|url=http://htx.pppl.gov/publication/Journal/CHT_Artem_PoP2007.pdf|publisher=Physics of Plasmas 14, 057106 (2007)|url-status=live|archive-url=https://web.archive.org/web/20100527095129/http://htx.pppl.gov/publication/Journal/CHT_Artem_PoP2007.pdf|archive-date=27 May 2010}}</ref><ref name=NTRS>{{cite conference |last1=Polzin |first1=K. A.|last2=Raitses |first2=Y. |last3=Gayoso |first3=J. C. |last4=Fisch |first4=N. J. |title=Comparisons in Performance of Electromagnet and Permanent-Magnet Cylindrical Hall-Effect Thrusters |conference=46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference |website=NASA Technical Reports Server|date=25 July 2010 |hdl=2060/20100035731 |hdl-access=free}}</ref> The cylindrical Hall thruster more readily lends itself to miniaturization and low-power operation than a conventional (annular) Hall thruster. The primary reason for cylindrical Hall thrusters is that it is difficult to achieve a regular Hall thruster that operates over a broad envelope from c.1&nbsp;kW down to c. 100&nbsp;W while maintaining an efficiency of 45–55%.<ref>{{cite conference |last1=Polzin |first1=K. A. |last2=Raitses |first2=Y. |last3=Merino |first3=E. |last4=Fisch |first4=N. J. |title=Preliminary Results of Performance Measurements on a Cylindrical Hall-Effect Thruster with Magnetic Field Generated by Permanent Magnets |conference=3rd Spacecraft Propulsion Subcommittee (SPS) meeting/JANNAF Interagency Propulsion Committee |website=NASA Technical Reports Server|date=8 December 2008 |hdl=2060/20090014067 |hdl-access=free}}</ref>