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دراسة تعجيل الالكترونات باستخدام تفاعل الليزر مع البلازما الممغنطة للاتصادمية == Study of Laser Acceleration of Electrons in a Magnetized Collisionless Plasma

Author name: امال محمد كنيوي العكايشي
Supervisor name: خالد عباس يحيى | محمد عبد الزهراء حبيب
General topic: Physics
Specific topic: Electronics Physics
Degree: Master
University: Al-Nahrain University - College Of Science - Physics Department
Language: English
University location: Baghdad
First pages:
Abstract: A theoretical and computational investigation was carried out in the field of laser - plasma interaction using the Finite Difference Method to study the acceleration of electrons with non - relativistic velocities in a non - magnetized and magnetized collisionless plasmas.First, a (Nd : YAG) laser pulse of 25 fs duration and 5x1015 W/cm2 intensity was assumed in the present study.When this laser pulse was allowed to interact with a stationary electron in vacuum, it was found that the electron is accelerated during the interaction only and returns to stationary state after the laser pulse has passed, in agreement with previous works.Also, the interaction of the same laser pulse with a collisionless plasma at electron density ne= 1x1018 cm - 3 was studied. It was noticed that the energy of the electron during the interaction has reached a maximum value of ~ 1 keV at laser pulse intensity of 5x1015 W/cm2, while the energy of the electron after the interaction reached ~ 15 eV for the same laser pulse intensity.Finally, the interaction of the same laser pulse with a plasma was studied at electron density ne=1x1018 cm - 3 in the presence of an external magnetic field for the three values of the field strength B= 60 MG, 70 MG and 80 MG. It was found that there is an increase in the acceleration of the electron to reach a maximum energy of ~ 19 keV at a laser pulse intensity of 5x1015 W/cm2 and an applied external magnetic field strength of 80 MG during the interaction. However, the electron energy after the interaction reached ~ 3 keV at a laser pulse intensity of 5x1015 W/cm2 and an applied external magnetic field strength of 70 MG. This is due to a sustainable generated laser wakefield of ~ 2x109 V/cm. Thus, it is concluded that an applied external magnetic field assists the acceleration of the electron and can subsidize for a high laser beam intensity

دراسة عامل الاستطارة الذرية للاشعة السينية للغلاف K والذرة كاملة للانظمة ذات الثلاث والاربع الكترونات == Studying x - ray atomic scattering form factor for K - shell and total atom for three and four electron system

Author name: رعد عيدان حليوت شنوف الكناني
Supervisor name: خليل هادي احمد البياتي
General topic: Physics
Specific topic: Electronics Physics
Degree: Master
University: Al-Nahrain University - College Of Science - Physics Department
Language: English
University location: Baghdad
First pages:
Abstract: استخدمت تقنية التجزئة لتحليل انظمة الثلاثة واربعة الكترونات الى ثلاثة ازواج من الدوال الموجية الاكترونية لبعض الايونات المشابهة لذرة الليثيوم وهي (Li, Be+, B++), وستة ازواج من الدوال الموجية الاكترونية لبعض الايونات المشابهة لذرة البيريليوم وهي (Li - , Be, B+) باستخدام دالة الموجة لهارتري فوك (Hartree - Fock ) والمطورة بواسطة كلمنتي وروتي .(Clementi and Roetti)ان هدف البحث هو دراسة عامل الاستطارة الذري للغلاف K والذرة كاملة لانظمة الثلاثة والاربعة الكترونات.تكمن الاهمية الفيزياوية لعامل الاستطارة الذرية في علاقتة بالعديد من الخواص الذرية المهمة مثل شدة الاستطارة المتشاكهة وشدة الاستطارة الكلية ودالة الاستطارة غير المتشاكهة والمقطع العرضي للاستطارة المتشاكهة والمقطع العرضي الكلي للاستطارة غير المتشاكهة وثابت الحجب المغناطيسي والمقطع العرضي التفاضلي لاستطارة الالكترونات بوساطة الذرات وعامل التركيب الهندسي .كما تم دراسة دالة توزيع الكثافة القطرية للجسيم الواحد , بحيث ان عامل الاستطارة الذري هو تحويل فورير (Fourier transform) لكثافة الالكترون ρ(r1) وان , دقة النتائج دققت بواسطة حساب الطاقة الكلية. جميع النتائج حسبت باستخدام الوحدات الذرية | The partitioning technique has been used to analyze the three and four electron systems into three - pairs electronic wave functions for Li - like ions (Li, Be+, B++) and six - pairs electronic wave functions for Be - like ions (Li - , Be, B+) by using Hartree - Fock wave functions of Clementi and Rotti.In this work the atomic scattering factor f(s) for K - shell and total atom for three and four electron systems are studied. The physical importance of this factor appears in its relation with the several important atomic properties such as, the coherent scattering intensity, the total scattering intensity, the incoherent scattering function, the coherent scattering cross section, the total incoherent cross section, the nuclear magnetic shielding constant, the differential cross section of electrons scattering from atom and the geometrical structure factor. Also the one particle radial density distribution function D(r) has been studied, where the atomic scattering factor f(s) is the Fourier transform of the electron density ρ(r1) and . The accuracy of results was checked by determining the total energy. All results are calculated in atomic units.