Measurement of microwave reflexion from a longitudinally magnetized plasma-filled co-axial wave-guide
The voltage reflexion coefficient from a vacuum-plasma boundary in a co-axial transmission line with an axial magnetic field B<sub>0</sub> applied has been measured. The results agree well with a previously published theory for conditions where the microwave-, plasma-, electron collision...
| Main Authors: | , |
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| Format: | Journal article |
| Language: | English |
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Cambridge University Press
1971
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| _version_ | 1797093727604310016 |
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| author | Oldfield, M Franklin, R |
| author_facet | Oldfield, M Franklin, R |
| author_sort | Oldfield, M |
| collection | OXFORD |
| description | The voltage reflexion coefficient from a vacuum-plasma boundary in a co-axial transmission line with an axial magnetic field B<sub>0</sub> applied has been measured. The results agree well with a previously published theory for conditions where the microwave-, plasma-, electron collision-, and electron cyclotron-frequencies are of the same order. A 9 GHz co-axial microwave probe is mounted along the axis of a 44 mm diameter, hydrogen driven, dry air filled, shock tube in an axial d.c. magnetic field. Shock ionized air (M<sub>s</sub>=9-14, T 4000°K, electron density n<sub>c</sub>=10<sup>17</sup> to 3x10<sup>19</sup>m<sup>-3</sup>, initial pressure p<sub>0</sub> = 1-10 Torr, electron collision frequency v = 10<sup>10</sup> to 10<sup>11</sup>/s) fills the coaxial line and partially reflects a microwave signal. Initially this probe, and a similar rectangular waveguide probe, were used with B<sub>0</sub> = 0 to calibrate the plasma (n<sub>c</sub>,v) in terms of the shock tube parameters (p<sub>0</sub>, M<sub>s</sub>). Measurement of the saturated-ion current to electrostatic probes inset into a flat plate in the shock tube flow showed that the sheath-edge ion density is close to the predicted free-stream equilibrium ion density. The apparent ionization potential derived from electrostatic probe results decreased as p<sub>0</sub> was reduced from 10 to 1 Torr. |
| first_indexed | 2024-03-07T04:04:25Z |
| format | Journal article |
| id | oxford-uuid:c5a7d06b-dc27-4113-aebe-e48db2728abc |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T04:04:25Z |
| publishDate | 1971 |
| publisher | Cambridge University Press |
| record_format | dspace |
| spelling | oxford-uuid:c5a7d06b-dc27-4113-aebe-e48db2728abc2022-03-27T06:32:39ZMeasurement of microwave reflexion from a longitudinally magnetized plasma-filled co-axial wave-guideJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:c5a7d06b-dc27-4113-aebe-e48db2728abcEngineering & allied sciencesEnglishOxford University Research Archive - ValetCambridge University Press1971Oldfield, MFranklin, RThe voltage reflexion coefficient from a vacuum-plasma boundary in a co-axial transmission line with an axial magnetic field B<sub>0</sub> applied has been measured. The results agree well with a previously published theory for conditions where the microwave-, plasma-, electron collision-, and electron cyclotron-frequencies are of the same order. A 9 GHz co-axial microwave probe is mounted along the axis of a 44 mm diameter, hydrogen driven, dry air filled, shock tube in an axial d.c. magnetic field. Shock ionized air (M<sub>s</sub>=9-14, T 4000°K, electron density n<sub>c</sub>=10<sup>17</sup> to 3x10<sup>19</sup>m<sup>-3</sup>, initial pressure p<sub>0</sub> = 1-10 Torr, electron collision frequency v = 10<sup>10</sup> to 10<sup>11</sup>/s) fills the coaxial line and partially reflects a microwave signal. Initially this probe, and a similar rectangular waveguide probe, were used with B<sub>0</sub> = 0 to calibrate the plasma (n<sub>c</sub>,v) in terms of the shock tube parameters (p<sub>0</sub>, M<sub>s</sub>). Measurement of the saturated-ion current to electrostatic probes inset into a flat plate in the shock tube flow showed that the sheath-edge ion density is close to the predicted free-stream equilibrium ion density. The apparent ionization potential derived from electrostatic probe results decreased as p<sub>0</sub> was reduced from 10 to 1 Torr. |
| spellingShingle | Engineering & allied sciences Oldfield, M Franklin, R Measurement of microwave reflexion from a longitudinally magnetized plasma-filled co-axial wave-guide |
| title | Measurement of microwave reflexion from a longitudinally magnetized plasma-filled co-axial wave-guide |
| title_full | Measurement of microwave reflexion from a longitudinally magnetized plasma-filled co-axial wave-guide |
| title_fullStr | Measurement of microwave reflexion from a longitudinally magnetized plasma-filled co-axial wave-guide |
| title_full_unstemmed | Measurement of microwave reflexion from a longitudinally magnetized plasma-filled co-axial wave-guide |
| title_short | Measurement of microwave reflexion from a longitudinally magnetized plasma-filled co-axial wave-guide |
| title_sort | measurement of microwave reflexion from a longitudinally magnetized plasma filled co axial wave guide |
| topic | Engineering & allied sciences |
| work_keys_str_mv | AT oldfieldm measurementofmicrowavereflexionfromalongitudinallymagnetizedplasmafilledcoaxialwaveguide AT franklinr measurementofmicrowavereflexionfromalongitudinallymagnetizedplasmafilledcoaxialwaveguide |