The Plasma-Material Interactions Facility at UCLA

Matlock, Taylor S.; Conversano, Ryan W.; Goebel, Dan M.; Wirz, Richard E.

doi:10.2514/6.2013-4132

Cited by 3 publications

(2 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The plasma discharge is controlled by commanding the gas flow and discharge current. The Pi facility operating conditions have been previously described by Matlock et al [11,17].…”

Section: Pi Facilitymentioning

confidence: 99%

In situplasma sputtering and angular distribution measurements for structured molybdenum surfaces

Matlock

Goebel

et al. 2017

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

We present in situ sputtering yield measurements of the time-dependent erosion of flat and micro-architectured molybdenum samples in a plasma environment. The measurements are performed using the plasma interactions (Pi) Facility at UCLA, which focuses a magnetized hollow cathode plasma to a material target with an exposure diameter of approximately 1.5 cm. During plasma exposure, a scanning quartz crystal microbalance (QCM) provides angular sputtering profiles that are integrated to estimate the total sputtering yield. This technique is validated to within the scatter of previous experimental data for a planar molybdenum target exposed to argon ion energies from 100 to 300 eV. The QCM is then used to obtain in situ measurements during a 17 h exposure of a micro-architectured-surface molybdenum sample to 300 eV incident argon ions. The time-dependent angular sputtering profile is shown to deviate from classical planar profiles, demonstrating the unique temporal and spatial sputtering effects of micro-architectured materials. Notably, the sputtering yield for the micro-architectured sample is initially much less than that for planar molybdenum, but then gradually asymptotes to the value for planar molybdenum after approximately 10 h as the surface features are eroded away.

show abstract

“…The plasma discharge is controlled by commanding the gas flow and discharge current. The Pi facility operating conditions have been previously described by Matlock et al [11,17].…”

Section: Pi Facilitymentioning

confidence: 99%

In situplasma sputtering and angular distribution measurements for structured molybdenum surfaces

Matlock

Goebel

et al. 2017

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…3 Discharge currents on the order of 100 A are collected radially at the anode across axial magnetic fields of several hundred Gauss despite relatively low collisionality. 4 Efforts to model our device, 5 for the dual purpose of optimization and eventual multiscale plasma-material interaction modeling, must include some accounting for the anomalously high electron transport. Similar devices, with strong low frequency, rotating modes are currently studied by a variety of groups 6-8 for the purpose of advancing the understanding of plasma instability induced transport.…”

Section: Introductionmentioning

confidence: 99%

An Investigation of Low Frequency Plasma Instabilities in a Cylindrical Hollow Cathode Discharge

Matlock¹,

Goebel²,

Wirz³

2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

Self Cite

View full text Add to dashboard Cite

A new plasma-material interactions testbed (refered to as the Pi facility) is under development at UCLA, which uses a 250 A lanthanum hexaboride (LaB6) hollow cathode coupled to a cylindrical copper anode to provide a plasma environment representative of electric propulsion (EP) and pulsed power (PP) devices to a target material nearly 1 m downstream. A steady ion bombardment energy for long duration testing is desired, which requires a steady (known) plasma potential adjacent to the target. Time-resolved plasma potential measurements reveal oscillations of ∼20% of the discharge voltage occuring near the anode exit at a fundamental frequency of 10-20 kHz, which is between the local ion cyclotron and lower hybrid frequencies (fci < f < f lh ). A 70-90 kHz oscillation dominates on-axis and couples non-linearly with the m=1, fundamental mode and a ∼60 kHz fluctuation that is localized just off-axis. The present article investigates these oscillations through intrusive probing across a range of discharge paramaters.

show abstract