BEGIN:VCALENDAR

VERSION:2.0

PRODID:-//wp-events-plugin.com//6.6.4.4//EN

TZID:Asia/Jerusalem

X-WR-TIMEZONE:Asia/Jerusalem
BEGIN:VEVENT

UID:0-256@aerospace.technion.ac.il

DTSTART;TZID=Asia/Jerusalem:20210324T163000

DTEND;TZID=Asia/Jerusalem:20210324T173000

DTSTAMP:20230525T063225Z

URL:https://aerospace.technion.ac.il/events/plasma-generation-and-accelera
 tion-mechanisms-in-capillary-capacitive-coupled-radio-frequency-thruster/

SUMMARY:Plasma Generation and Acceleration Mechanisms in Capillary Capaciti
 ve Coupled Radio-Frequency Thruster
DESCRIPTION:Lecturer:Arsad Quraishi\n Faculty:Department of Aerospace Engin
 eering\n Institute:Technion – Israel Institute of Technology\n Location:
 https://technion.zoom.us/j/8167918651\n Zoom: \n Abstract: \n Details: \n 
 Capacitively coupled radio-frequency thrusters (CCRFT) are an attractive p
 ropulsion option for nanosatellites due to their low operating power\, rel
 atively high thrust\, and low erosion of the electrodes. Such thrusters ca
 n serve as a direct replacement to cold gas thrusters\, achieving higher s
 pecific impulse. CCRFTs produce thrust by generating a gaseous electric di
 scharge within a dielectric tube by means of RF power. The RF circuit coup
 les to the plasma via a capacitor therefore blocking the dc current compon
 ent. The discharge heats the gas inside the tube\, and the heated gas is e
 jected from the tube tip or nozzle to produce thrust.\n A capillary capac
 itively coupled radio-frequency thruster (C3RFT) is being developed at the
  Aerospace Plasma Laboratory\, Technion. The small diameter of the dielect
 ric tube allows operation of the device in very low flow rates 4-16 SCCM i
 n Ar. The thruster utilizes a non-symmetric electrode arrangement and no n
 ozzle. At constant input power\, the thrust is shown to increase linearly 
 with the flow rate. At an input power of 14 W and a flow rate of 8 SCCM\, 
 the thrust increases significantly by 60 % compared to the cold flow case\
 , for a total thrust of ≈ 160 µN and specific impulse ≈ 70 s in Ar.\n
 The C3RFT discharge is shown to be sensitive to electrode polarity. When t
 he larger back electrode is powered and the front electrode grounded a mod
 e transition of the discharge is observed. This phenomenon is marked by an
  appearance of bright plasma exhaust and reduction in input power from ≈
  15.17 W to ≈ 9 W. After the transition\, the thrust to power ratio incr
 eases by 25 %. A sheath breakdown model is proposed to explain this transi
 tion. The thrust can be completely attributed to gas dynamic acceleration.
 \nComputational fluid dynamics (CFD) plasma simulations were performed to 
 analyze the spatial characteristics of the discharge in the C3RFT. The sim
 ulated thruster performance is found to be in good agreement with measurem
 ents. For a grounded back electrode case\, the plasma potential is found t
 o drop near the smaller front powered electrode creating a negative DC bia
 s\, in accordance with classical theory of asymmetric capacitive discharge
 . Electrons in sheath are heated to ~ 6 eV whereas in the rest of the capi
 llary the electron temperature ~ 2 eV. The plasma density is 1019 m-3 wher
 eas excited argon species are 1020 m-3.\nZoom Meeting
CATEGORIES:Seminars
LOCATION:https://technion.zoom.us/j/8167918651

END:VEVENT

BEGIN:VTIMEZONE

TZID:Asia/Jerusalem

X-LIC-LOCATION:Asia/Jerusalem

BEGIN:STANDARD

DTSTART:20201025T010000

TZOFFSETFROM:+0300

TZOFFSETTO:+0200

TZNAME:IST

END:STANDARD

END:VTIMEZONE
END:VCALENDAR