{"title":"A steerable plasma microwave mirror","authors":"I. Alexeff, T. Anderson","doi":"10.1109/PLASMA.2009.5227631","DOIUrl":null,"url":null,"abstract":"We have developed a steerable plasma microwave mirror based on our previous work on the reflection of microwaves on a plasma slab. We have discovered that for plasma densities above microwave cutoff, the phase of the reflection varies continuously from a voltage antinode at the plasma surface when the plasma density just reaches microwave cutoff, to a voltage node at the plasma surface when the plasma density is much larger than that required for microwave cutoff. An analogy to the reflection at the end of a coaxial cable is that the first case corresponds to an open line (displacement and conduction currents equal and opposite), and the second case corresponds to a shorted line (conduction current much greater than displacement current). The operating plasma mirror as presently designed comprises a surface of plasma tubes. By programming the plasma density in the various tubes, the reflected microwaves experience a varying phase shift from tube to tube and the reflected beam is steered in analogy to the way an emitted microwave beam is steered by a phased transmission antenna array. The time required for reconfiguring the beam direction corresponds to the time required for plasma modification-in this case, a few milliseconds.","PeriodicalId":6359,"journal":{"name":"2008 IEEE 35th International Conference on Plasma Science","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"2008 IEEE 35th International Conference on Plasma Science","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/PLASMA.2009.5227631","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
We have developed a steerable plasma microwave mirror based on our previous work on the reflection of microwaves on a plasma slab. We have discovered that for plasma densities above microwave cutoff, the phase of the reflection varies continuously from a voltage antinode at the plasma surface when the plasma density just reaches microwave cutoff, to a voltage node at the plasma surface when the plasma density is much larger than that required for microwave cutoff. An analogy to the reflection at the end of a coaxial cable is that the first case corresponds to an open line (displacement and conduction currents equal and opposite), and the second case corresponds to a shorted line (conduction current much greater than displacement current). The operating plasma mirror as presently designed comprises a surface of plasma tubes. By programming the plasma density in the various tubes, the reflected microwaves experience a varying phase shift from tube to tube and the reflected beam is steered in analogy to the way an emitted microwave beam is steered by a phased transmission antenna array. The time required for reconfiguring the beam direction corresponds to the time required for plasma modification-in this case, a few milliseconds.