Mackenzie's Demon with instabilities

Yip, Chi-Shung; Sheehan, J. P.; Hershkowitz, N.; Severn, Greg

doi:10.1088/0963-0252/22/6/065002

Cited by 29 publications

(59 citation statements)

References 18 publications

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“…Measurements of the plasma potential and plasma electron temperature were made in the afterglow of a capacitively coupled RF plasma. The slow-sweep probe method [26][27][28] was used in conjunction with the inflection point in the limit of zero emission emissive probe technique 22 to obtain emissive probe I-V traces as a function of time. This is the first time that the inflection point technique was used to make time-resolved plasma potential measurements, a great asset for this method, which is the most accurate of the emissive probe techniques.…”

Section: Discussionmentioning

confidence: 99%

“…If, however, the temporal response being measured is periodic, the slow-sweep probe method has good accuracy with a simpler setup. [26][27][28] To execute this method, the probe is biased at a constant potential and current is measured as a function of time. That procedure is performed for a range of bias voltages, and by transposing the data, probe current versus bias voltage at various times can be obtained.…”

Section: Slow-sweep Probe Methodsmentioning

confidence: 99%

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Emissive sheath measurements in the afterglow of a radio frequency plasma

et al. 2014

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The difference between the plasma potential and the floating potential of a highly emissive planar surface was measured in the afterglow of a radio frequency discharge. A Langmuir probe was used to measure the electron temperature and an emissive probe was used to measure the spatial distribution of the potential using the inflection point in the limit of zero emission technique. Time-resolved measurements were made using the slow-sweep method, a technique for measuring time-resolved current-voltage traces. This was the first time the inflection point in the limit of zero emission was used to make time-resolved measurements. Measurements of the potential profile of the presheath indicate that the potential penetrated approximately 50% farther into the plasma when a surface was emitting electrons. The experiments confirmed a recent kinetic theory of emissive sheaths, demonstrating that late in the afterglow as the plasma electron temperature approached the emitted electron temperature, the emissive sheath potential shrank to zero. However, the difference between the plasma potential and the floating potential of a highly emissive planar surface data appeared to be much less sensitive to the electron temperature ratio than the theory predicts. V

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Section: Discussionmentioning

confidence: 99%

Section: Slow-sweep Probe Methodsmentioning

confidence: 99%

Emissive sheath measurements in the afterglow of a radio frequency plasma

et al. 2014

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“…In MacKenzie's work, it was argued that a thin positively biased wire preferentially collects low energy electrons because of orbital motion effects, leading to an effective heating effect [50]. However, it was also shown that a biased planar electrode leads to essentially the same result due to the mechanism described above [51].…”

Section: Global Non-ambipolar Flowmentioning

confidence: 99%

“…Yip and Hershkowitz [51] presented a model for the oscillation period based on a rate equation for electron generation and loss. The model was able to describe the qualitative features of their experiment, where fireballs formed near a biased wire array.…”

Section: Hysteresismentioning

confidence: 99%

Interaction of biased electrodes and plasmas: sheaths, double layers, and fireballs

Baalrud

Scheiner

Yee

et al. 2020

Plasma Sources Sci. Technol.

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Biased electrodes are common components of plasma sources and diagnostics. The plasma-electrode interaction is mediated by an intervening sheath structure that influences properties of the electrons and ions contacting the electrode surface, as well as how the electrode influences properties of the bulk plasma. A rich variety of sheath structures have been observed, including ion sheaths, electron sheaths, double sheaths, double layers, anode glow, and fireballs. These represent complex self-organized responses of the plasma that depend not only on the local influence of the electrode, but also on the global properties of the plasma and the other boundaries that it is in contact with. This review summarizes recent advances in understanding the conditions under which each type of sheath forms, what the basic stability criteria and steady-state properties of each are, and the ways in which each can influence plasma-boundary interactions and bulk plasma properties. These results may be of interest to a number of application areas where biased electrodes are used, including diagnostics, plasma modification of materials, plasma sources, electric propulsion, and the interaction of plasmas with objects in space.

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“…Combining this with the steady-state Langmuir condition of Eq. An interesting observation from experiments is that increasing the size of the electrode decreases the critical bias [89,2]. Eq.…”

Section: Anode Spot Onsetmentioning

confidence: 99%

Theory and simulation of electron sheaths and anode spots in low pressure laboratory plasmas

Scheiner¹

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ACKNOWLEDGEMENTSThis work benefited from the input, help, and feedback of several people. This research was done in collaboration with Scott Baalrud, Matt Hopkins, Ed Barnat, and Ben Yee. Scott has been a great advisor. He took the time to check the details of nearly all of my work, pointing out countless mistakes and making several suggestions along the way. This not only included research results, but also seminar and conference talks, papers, and abstracts. I'm grateful for the encouragement and feedback when exploring new ideas and the pressure to stay focused and not stray too far from the current task at hand. Matt Hopkins was my mentor during the year I spent at Sandia National Lab under the O ce of Science Graduate Student Research program. Matt sponsored my application to the SCGSR program. Without his e↵ort, simulation of plasmas would not have played as great of a role as it has. I consider my experience simulating plasma experiments at Sandia to have been the most transformative of my graduate career. This will be invaluable as I move on to study new problems. At Sandia, I benefited from weekly discussions with Ed, Matt, and Ben on di↵erent issues relating to their various research topics in low temperature plasmas. Being in an environmentsurrounded by other plasma physicists working on related problems helped me distinguish which problems were interesting and useful to other people working in the field. The discussion of experimental results with Ben and Ed helped me to develop an understanding of these topics and to understand what things are and are not di cult to measure in the lab. Eventually I learned to stop asking for the impossible, although Ed may disagree. I enjoyed the hours spent talking plasma physics (or other less useful topics) around Andy Fierro's giant candy bowl with Ben, Ricky Tang, and Jim Franek. Also, the near daily breakfast burrito trips that Andy and I took made the food further east seem bland and nearly unbearable.At Iowa, there were several people who made day to day life more interesting. The two most notable are Ryan Hood and Nathaniel Sha↵er. Ryan always stopped by to talk about the latest thing that happened in the lab, or the latest Regular Car Review, and was always kind enough to show me his experiment and latest measurements. I've known Nathaniel since 2009 and am glad to have had a friend with whom I could bounce ideas o↵ of for so many years. I have no doubt that our various 'idiot checks' have vastly reduced the number of mistakes that could have been in these chapters. I have no doubt that both Nathaniel and Ryan will be great plasma physicists.Finally, I want to thank my family and friends for their support, especially my fiancè Mary ii for understanding the many late nights and stress filled days. I could not have done this without her support and love. ABSTRACTElectrodes in low pressure laboratory plasmas have a multitude of possible sheath structures when biased at a large positive potential. When the size of the electrode is small enough the electrode bia...

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Mackenzie's Demon with instabilities

Cited by 29 publications

References 18 publications

Emissive sheath measurements in the afterglow of a radio frequency plasma

Emissive sheath measurements in the afterglow of a radio frequency plasma

Interaction of biased electrodes and plasmas: sheaths, double layers, and fireballs

Theory and simulation of electron sheaths and anode spots in low pressure laboratory plasmas

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