اثر پديدۀ مگي-ريگي-لدوك روي موج صوتي ترموالاستيك و موج گرمايي ايجادشده با پالس ليزر

Effect of Maggi-Righi-Leduc phenomena on thermo-elastic acoustic wave and thermal wave generated by laser pulse

در اﻳﻦ ﻣﻘﺎﻟﻪ ﺑﻪ ﻣﻄﺎﻟﻌﺔ اﺛﺮ ﻣﻴﺪان ﻣﮕﻨﺘﻮاﺳﺘﺎﺗﻴﻚ ﺑﺮ اﻧﺘﺸﺎر اﻣﻮاج ﺻﻮﺗﻲ ﺗﺮﻣﻮاﻻﺳﺘﻴﻚ و ﻣﻮج ﮔﺮﻣﺎﻳﻲ اﻳﺠﺎدﺷﺪه ﺑـﺎ ﺗـﺎﺑﺶ ﻟﻴـﺰر روي ﻓﻠﺰ ﺧﻮاﻫﻴﻢ ﭘﺮداﺧﺖ. ﻣﻜﺎﻧﻴﺰم ﻣﺸﺘﺮك در ﺗﻤﺎم ﺑﺮﻫﻢﻛﻨﺶﻫﺎي ﭘﺎﻟﺲ ﻟﻴﺰر ﺑﺎ ﻓﻠﺰات، اﻳﺠﺎد ﻣـﻮج ﺻـﻮﺗﻲ ﺗﺮﻣﻮاﻻﺳـﺘﻴﻚ و ﻣﻮج ﮔﺮﻣﺎﻳﻲ اﺳﺖ. در ﭘﺎﻟﺲﻫﺎي ﺑﺎ اﻧﺮژيﻫﺎي زﻳﺎد، اﻣﻜﺎن وﻗﻮع ﻓﺮاﻳﻨﺪﻫﺎي ﻣﺨﺮب ﻧﻴﺰ وﺟﻮد دارد. ﺑـﺮ اﺳـﺎس ﭘﺪﻳـﺪة ﻣﮕـﻲ -رﻳﮕﻲ- ﻟﺪوك، وﺟﻮد ﻣﻴﺪان ﻣﻐﻨﺎﻃﻴﺴﻲ اﺳﺘﺎﺗﻴﻚ ﻋﻤﻮد ﺑﺮ ﺻﻔﺤﺔ ﺑﺮﻫﻢﻛﻨﺶ، ﻣﻲﺗﻮاﻧﺪ اﻧﺘﺸﺎر ﻣﻮج ﮔﺮﻣﺎﻳﻲ اﻳﺠﺎدﺷﺪه در ﻫﻤـﺔ ﻓﺮاﻳﻨﺪﻫﺎ را ﺗﺎ ﺣﺪودي ﻣﺤﺪود ﺳﺎزد. ﻓﺮاﻳﻨﺪ ﻓﻴﺰﻳﻜﻲ ﺑﻪ دام اﻓﺘﺎدن ﮔﺮﻣﺎ و آزﻣﺎﻳﺶ ﺗﺠﺮﺑﻲ اﻳﻦ ﻓﺮاﻳﻨﺪ در اﻳﻦ ﻣﻘﺎﻟـﻪ ﻣﻮرد ﺑﺮرﺳـﻲ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. ﺣﺪاﻛﺜﺮ ﻛﺎﻫﺶ اﻧﺘﺸﺎر ﺟﺒﻬﺔ ﻣﻮج ﮔﺮﻣﺎﻳﻲ اﻳﺠﺎدﺷﺪه در ﺷﺒﻴﻪﺳﺎزي و در ﺣﻀﻮر ﻣﻴﺪان 1 ﺗﺴﻼ ﺑﻪﻣﻴﺰان 18±1 درﺻﺪ ﺑﻪ دﺳﺖ آﻣﺪ. در ﺗﺼﻮﻳﺮ ﮔﺮﻣﺎﻳﻲ ﮔﺮﻓﺘﻪﺷﺪه از ﻣﺤﻞ ﺑﺮﻫﻢﻛﻨﺶ، اﻳﻦ ﻛﺎﻫﺶ ﺑﻪﻣﻴﺰان 1/1±4/5 درﺻﺪ ﻣﺸﺎﻫﺪه ﺷﺪ.

In this paper we will study the effect of magneto static field on propagation of sound wavegenerated in metal by pulsed laser in thermo elastic regime . Almost the common mechanism in all interactions of laser pulse and metal is the thermo elastic mechanism mechanism. Ablation regime can occur and is possible in higher laser pulse energy. According to the effect of Maggi Righi Leduce phenomena, presence of magnetio static field normal to the surface of interaction of laser pulse and metal can almost trap the propagation of thermal wave in thermo elastic regime. The physical mechanism of this trapping and experimental results of this mechanism have investigated in this paper. We obtained maximum reduction in 2 D thermo elastic wave propagation around 18 ± 1 % in simulation and at presence of 1 tesla B field and qualitativelywe obtained 4.5 ± 1.1 % reduction of the width of thermal image in experiment.