title: A microwave interferometer for small and tenuous plasma density measurements.
abstract: The non-intrusive density measurement of the thin plasma produced by a mini-helicon space thruster (HPH.com project) is a challenge, due to the broad density range (between 10(16) m(-3) and 10(19) m(-3)) and the small size of the plasma source (2 cm of diameter). A microwave interferometer has been developed for this purpose. Due to the small size of plasma, the probing beam wavelength must be small (λ = 4 mm), thus a very high sensitivity interferometer is required in order to observe the lower density values. A low noise digital phase detector with a phase noise of 0.02° has been used, corresponding to a density of 0.5 × 10(16) m(-3).
authors.affiliation: ENEA CR Frascati, Via E. Fermi 45, 00044 Frascati, Italy. onofrio.tudisco@enea.it
authors.forename: O
authors.initials: O
authors.lastname: Tudisco
authors.forename: A
authors.initials: A
authors.lastname: Lucca Fabris
authors.forename: C
authors.initials: C
authors.lastname: Falcetta
authors.forename: L
authors.initials: L
authors.lastname: Accatino
authors.forename: R
authors.initials: R
authors.lastname: De Angelis
authors.forename: M
authors.initials: M
authors.lastname: Manente
authors.forename: F
authors.initials: F
authors.lastname: Ferri
authors.forename: M
authors.initials: M
authors.lastname: Florean
authors.forename: C
authors.initials: C
authors.lastname: Neri
authors.forename: C
authors.initials: C
authors.lastname: Mazzotta
authors.forename: D
authors.initials: D
authors.lastname: Pavarin
authors.forename: F
authors.initials: F
authors.lastname: Pollastrone
authors.forename: G
authors.initials: G
authors.lastname: Rocchi
authors.forename: A
authors.initials: A
authors.lastname: Selmo
authors.forename: L
authors.initials: L
authors.lastname: Tasinato
authors.forename: F
authors.initials: F
authors.lastname: Trezzolani
authors.forename: A A
authors.initials: AA
authors.lastname: Tuccillo