Feedback effect on flute dynamics in a mirror machine

Autor:	Ilan Be'ery, Omri Seemann
Rok vydání:	2015
Předmět:	Physics media_common.quotation_subject Phase (waves) Phase margin Plasma Mechanics Condensed Matter Physics Rotation Asymmetry Instability Amplitude Nuclear Energy and Engineering Positive feedback media_common
Zdroj:	Plasma Physics and Controlled Fusion. 57:085005
ISSN:	1361-6587 0741-3335
Popis:	The effect of active feedback on flute instability is experimentally studied in a table-top mirror machine. Changing the plasma conditions from mirror-loss dominated to flute-loss dominated, it is demonstrated that while the feedback has no effect on plasma density in the first case, it increases the plasma density by up to 50% in the second case. Measurements of the dependence of instability amplitude on feedback gain show that large gain stimulates high frequency perturbations. The period of these perturbations corresponds to the inherent delay of immersed electrode feedback. Variation of the spatial phase between the input and output of the phase reveals a large asymmetry between positive and negative phase shifts. A simplified model is introduced to explain how a negative phase shift causes positive feedback between the external feedback and the centrifugally driven rotation.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::e9b241573f8bcfe3f6e0b4eef0f0b0a9 https://doi.org/10.1088/0741-3335/57/8/085005 Zobrazit plný text záznamu