MATSIN YANAYI MILIYAN ƊAYA A KAN TEBURIN DAKIN GWAJI

Matsin megabar ɗaya — gigapascal 100, kusan sau miliyan na matsin yanayi — yana sake rubuta ƙa’idojin abu. Zai iya mayar da abubuwan da ba sa gudanar da wutar lantarki su zama ƙarfe, daskararru marasa tsari su zama lu’ulu’u (crystals), abubuwa masu saurin amsawa su zama marasa amsawa. Matse samfurori a hankali tsakanin maƙeran lu’u-lu’u (diamond anvils) yana cikin ikon dakin gwaji ɗaya na jami’a. Kaiwa megabar da raƙuman girgiza (shock waves) wani labari ne daban: ya dogara galibi ne kan lesar na matakin kilojoule ko bindigogin iskar gas masu harba harsasai, a dakunan gwaje-gwaje na ƙasa da manyan cibiyoyi waɗanda ke yin ’yan harbi kaɗan a awa ɗaya, ko a rana ɗaya.

Zoben haske da ke tattara raƙumin girgiza

Ƙungiyar Keith Nelson a Cibiyar Fasaha ta Massachusetts (MIT), tare da abokan aiki a Dakin Bincike na Sojojin Amurka, Jami’ar Rennes, Jami’ar Massachusetts Amherst da Dakin Gwaje-gwaje na Ƙasa na Lawrence Livermore, sun fara daga wata dabara da aka sani. A siffanta bugun lesar ya zama zobe da axicon, wani prism mai siffar mazugi, sannan a tattara shi a kan wani layin ruwa mai kaurin ’yan dubunnan micron. Zoben da ya haskaka yana tururi kuma yana harba raƙumin girgiza wanda ke haɗuwa zuwa tsakiya. Yayin da yake ƙanƙanta zuwa sararin da ke ƙara ƙanƙanta, matsinsa yana hauhawa da sauri. Da kanta, wannan hanyar ta kai dubunnan gigapascal.

Sabon ra’ayin shi ne a harba zobe da yawa, ɗaya bayan ɗaya: mafi faɗi da farko, sannan ƙanana, tare da tazarar ’yan nanosecond. Ana daidaita girman zobe da jinkiri ta yadda kowane sabon zobe zai haskaka daidai inda raƙumin girgiza mai haɗuwa yake wucewa — sharaɗin “daidaita gudu” (speed matching). Sannan kowane zobe yana ƙara turawarsa ga gaban raƙumi ɗaya maimakon harba wani daban.

Bugun lesar huɗu daga lesar ɗaya

Lesar ɗaya (1,064 nm, bugun picosecond 200, millijoule 100 a mafi yawa) ana raba ta zuwa bugu huɗu masu jinkirin kusan nanosecond 10 kowanne, kuma kowanne yana wucewa ta nasa nau’in axicon biyu. A kan samfurin, zoben suna da radius na micrometre 169, 134, 105 da 75; jinkirin da aka auna a tsakaninsu ya kasance nanosecond 11.1, 10.7 da 9.2. Abin da ake nufa shi ne layin ruwa mai kaurin micrometre 25 wanda aka yi duhu da kashi 5% na baƙin tawada na kasuwa (ƙananan ƙwayoyin carbon), an matse shi tsakanin tagogin sapphire biyu.

Kyamarar streak tana bin raƙumin girgizar tare da wani layi da ke ratsa tsakiya. Da zobe ɗaya, yana kaiwa wurin tattarawa cikin kusan nanosecond 62. Da kowane ƙarin zobe, tafiyar a kan kusan micrometre 160 na ƙarshe tana gajarta: raƙumin yana tafiya da sauri, don haka ya fi ƙarfi. Tsarin ya yi kusan harbi ɗaya a minti, an iyakance shi ne saboda motsa samfurin da hannu; an ɗauki kusan harbi 1,000 masu amfani.

Gigapascal 400 — an lissafa, ba a auna ba tukuna

Ba a auna matsin kansa ba. Ƙungiyar ta gudanar da kwaikwayon hydrodynamic tare da girman zobe da jinkiri iri ɗaya, tana daidaita ma’auni ɗaya kawai — makamashin da kowane zobe yake ajiyewa a zahiri — har sai hanyar raƙumin da aka kwaikwaya ta dace da wadda aka auna. Mafi kyawun dacewa ya zo a kusan millijoule 2 a kowane zobe, daga 4.5 da aka harba. Sannan kwaikwayon yana ba da yanayin kusa da wurin tattarawa: fiye da gigapascal 400 a micrometre 1 daga tsakiya, yawa (density) na gram 4 a kowane centimita mai siffar sukari da kusan kelvin 5,700.

Ribar ta fi haɗawa kawai. A cikin kwaikwayon, zobe huɗu da aka harba daban-daban za su kai matsi mafi girma waɗanda tare suka kai gigapascal 280 kawai; idan aka harba su a jere, suna kaiwa kusan 420. Marubutan sun daidaita matsi mafi girma idan aka kwatanta da adadin zobe da wani lanƙwasa na lura (phenomenological), P = a·exp(N/b) + c, kuma sun jaddada cewa siffantawa ce a kan ƙaramin zangon da aka bincika, ba doka ta duniya ba.

Wani abu mai ban mamaki ya rage ba a bayyana shi ba. Kafin raƙumin girgizar ya iso, tsakiyar samfurin tana yin duhu, kusan nanosecond 30 bayan harba lesar — gudun da ya dace da raƙuman Rayleigh a cikin sapphire. An bar asalinsa ga aikin nan gaba.

Ƙananan rubuce-rubuce

Marubutan da kansu sun bayyana iyakokin. Iƙirarin megabar ya dogara ne kan kwaikwayo, ba kan na’urar auna matsi kai tsaye ba. Lissafin yanayi (equations of state) da aka yi amfani da su ga ruwa da sapphire sun fito ne daga rahotannin cikin gida na Livermore, ba daga tushe na jama’a da aka yi wa bita ba, don haka ba za a iya duba ma’aunin matsi na ainihi da kansa ba. Daidaitawar tana amfani da ma’auni ɗaya mai ’yanci da harbi mafi ƙarfi, kuma kwaikwayon yana ɗaukar cikakken daidaiton da’ira; ƙungiyar ta ƙiyasta cewa ainihin wurin tattarawa bai kai micrometre 5 ba, kuma kwaikwayon har yanzu yana ba da matsin megabar a micrometre 5 daga tsakiya.

Mataki na gaba shi ne a auna wurin tattarawa kai tsaye, misali da hasken X-ray da ke bayyana yawan samfurin. Marubutan kuma suna ganin damar haɓaka: ƙarin zobe, ƙarin makamashi, rabon wannan makamashi tsakanin zobe da hikima — kuma, ta hanyar ɓata lokacin zobe da gangan, jerin raƙuman girgiza masu laushi waɗanda za su iya matse abu yayin da suke rage zafinsa.