{"title":"Direct Laser-Driven Electron Acceleration and Energy Gain in Helical Beams","authors":"E. Moln'ar, D. Stutman","doi":"10.1155/2021/6645668","DOIUrl":null,"url":null,"abstract":"<jats:p>A detailed study of direct laser-driven electron acceleration in paraxial Laguerre–Gaussian modes corresponding to helical beams <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M1\">\n <msub>\n <mrow>\n <mtext>LG</mtext>\n </mrow>\n <mrow>\n <mn>0</mn>\n <mi>m</mi>\n </mrow>\n </msub>\n </math>\n </jats:inline-formula> with azimuthal modes <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M2\">\n <mi>m</mi>\n <mo>=</mo>\n <mfenced open=\"{\" close=\"}\" separators=\"|\">\n <mrow>\n <mn>1,2,3,4,5</mn>\n </mrow>\n </mfenced>\n </math>\n </jats:inline-formula> is presented. Due to the difference between the ponderomotive force of the fundamental Gaussian beam <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M3\">\n <msub>\n <mrow>\n <mtext>LG</mtext>\n </mrow>\n <mrow>\n <mn>00</mn>\n </mrow>\n </msub>\n </math>\n </jats:inline-formula> and helical beams <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M4\">\n <msub>\n <mrow>\n <mtext>LG</mtext>\n </mrow>\n <mrow>\n <mn>0</mn>\n <mi>m</mi>\n </mrow>\n </msub>\n </math>\n </jats:inline-formula>, we found that the optimal beam waist leading to the most energetic electrons at full width at half maximum is more than twice smaller for the latter and corresponds to a few wavelengths <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M5\">\n <mi mathvariant=\"normal\">Δ</mi>\n <msub>\n <mrow>\n <mi>w</mi>\n </mrow>\n <mrow>\n <mn>0</mn>\n </mrow>\n </msub>\n <mo>=</mo>\n <mfenced open=\"{\" close=\"}\" separators=\"|\">\n <mrow>\n <mn>6,11,19</mn>\n </mrow>\n </mfenced>\n <msub>\n <mrow>\n <mi>λ</mi>\n </mrow>\n <mrow>\n <mn>0</mn>\n </mrow>\n </msub>\n </math>\n </jats:inline-formula> for laser powers of <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M6\">\n <msub>\n <mrow>\n <mi>P</mi>\n </mrow>\n <mrow>\n <mn>0</mn>\n </mrow>\n </msub>\n <mo>=</mo>\n <mfenced open=\"{\" close=\"}\" separators=\"|\">\n <mrow>\n <mn>0.1</mn>\n <mo>,</mo>\n <mn>1,10</mn>\n </mrow>\n </mfenced>\n </math>\n </jats:inline-formula> PW. We also found that, for azimuthal modes <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M7\">\n <mi>m</mi>\n <mo>≥</mo>\n <mn>3</mn>\n </math>\n </jats:inline-formula>, the optimal waist should be smaller than <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M8\">\n <mi mathvariant=\"normal\">Δ</mi>\n <msub>\n <mrow>\n <mi>w</mi>\n </mrow>\n <mrow>\n <mn>0</mn>\n </mrow>\n </msub>\n <mo><</mo>\n <mn>19</mn>\n <msub>\n <mrow>\n <mi>λ</mi>\n </mrow>\n <mrow>\n <mn>0</mn>\n </mrow>\n </msub>\n </math>\n </jats:inline-formula>. Using these optimal values, we have observed that the average kinetic energy gain of electrons is about an order of magnitude larger in helical beams compared to the fundamental Gaussian beam. This average energy gain increases with the azimuthal index <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M9\">\n <mi>m</mi>\n </math>\n </jats:inline-formula> leading to collimated electrons of a few 100 MeV energy in the direction of the laser propagation.</jats:p>","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":"2 1","pages":"1-13"},"PeriodicalIF":1.1000,"publicationDate":"2021-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Laser and Particle Beams","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1155/2021/6645668","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"PHYSICS, APPLIED","Score":null,"Total":0}
引用次数: 2
Abstract
A detailed study of direct laser-driven electron acceleration in paraxial Laguerre–Gaussian modes corresponding to helical beams with azimuthal modes is presented. Due to the difference between the ponderomotive force of the fundamental Gaussian beam and helical beams , we found that the optimal beam waist leading to the most energetic electrons at full width at half maximum is more than twice smaller for the latter and corresponds to a few wavelengths for laser powers of PW. We also found that, for azimuthal modes , the optimal waist should be smaller than . Using these optimal values, we have observed that the average kinetic energy gain of electrons is about an order of magnitude larger in helical beams compared to the fundamental Gaussian beam. This average energy gain increases with the azimuthal index leading to collimated electrons of a few 100 MeV energy in the direction of the laser propagation.
期刊介绍:
Laser and Particle Beams is an international journal which deals with basic physics issues of intense laser and particle beams, and the interaction of these beams with matter. Research on pulse power technology associated with beam generation is also of strong interest. Subjects covered include the physics of high energy densities; non-LTE phenomena; hot dense matter and related atomic, plasma and hydrodynamic physics and astrophysics; intense sources of coherent radiation; high current particle accelerators; beam-wave interaction; and pulsed power technology.