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Article
Monte Carlo Simulation of Electronic Kinetics in Gas Discharge

Authors: A.B. Kadhem --- B.H. Hamad
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2005 Volume: 1 Issue: 3 Pages: 3-5
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

The phenomenon of electrical gas discharge is present in manyapplications of plasma physics. Calculation of electrons motion tracingin gases are described. The backscattering probability of electrons tothe cathode has been estimated for values of E/P0 ratio from 10 to 200V.cm-1.torr-1 and for emission energies up to the lowest excitationpotential. The primary ionization coefficients and drift velocities wereevaluated for values of E/P0 ratio from 20 to 400 V.cm-1.torr-1. Theequilibrium of swarm with the field was considered in detail. It isshown that for uniform fields, deviations from exponential growth ofcurrent with increasing electrode separation occur if the interelectrodevoltage is not at least three times the mean energy ofelectrons impinging on the anode.


Article
Analysis of Boltzmann Equation for SF6 and Some Gas-Mixture Discharges at Critical Field Condition

Authors: Abdulrida S. Hasaani --- Mukhlis M. Ismail
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2016 Volume: 12 Issue: 1 Pages: 31-34
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

The energy electron distribution function at a particular reduced electric field E/p (where E is the electric field and p is the gas pressure) for SF6+He and SF6+Ar mixtures has been studied. The distribution function has been calculated as a function of percentage mixture ratio (k) ranging from zero (pure SF6) to 100% (for He or Ar) at (E/p)crt. On the other stage, these distribution functions are also studied as a function of (k) at a particular (E/p)crt. under which the breakdown occurs for the same gas mixtures. The (E/p)crt calculation is adopted to explain the discrepancy of the distribution function for gas mixtures. It is also found that the distribution function for gas mixtures at (E/p)crt. and for any value of (k) are identical.


Article
Analysis of Boltzmann Equation for SF6 and Some Gas-Mixture Discharges at Critical Field Condition
تحليل معادلة بولتزمان لسداسي فلوريد الكبريت وبعض تفريغات الخلائط الغازية تحت شرط المجال الحرج

Authors: Abdulrida S. Hasaani --- Mukhlis M. Ismail
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2017 Volume: 13 Issue: 1 Pages: 31-34
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

The energy electron distribution function at a particular reduced electric field E/p (where E is the electric field and p is the gas pressure) for SF6+He and SF6+Ar mixtures has been studied. The distribution function has been calculated as a function of percentage mixture ratio (k) ranging from zero (pure SF6) to 100% (for He or Ar) at (E/p)crt. On the other stage, these distribution functions are also studied as a function of (k) at a particular (E/p)crt. under which the breakdown occurs for the same gas mixtures. The (E/p)crt calculation is adopted to explain the discrepancy of the distribution function for gas mixtures. It is also found that the distribution function for gas mixtures at (E/p)crt. and for any value of (k) are identical.


Article
Applications Aspects of the Diffusion of Slow Electrons in the Ionospheric Gases
الواجهات التطبيقية لانتشار الإلكترونات الواطئة الطاقة في غازات طبقات الجو

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Abstract

The paper presents the results of precise of the calculations of the diffusion of slow electrons in ionospheric gases, such as, (Argon – Hydrogen mixture, pure Nitrogen and Argon – Helium – Nitrogen) in the presence of a uniform electric field and temperature 300 Kelvin. Such calculations lead to the value Townsend's energy coefficient (KT) as a function of E/P (electric field strength/gas pressure), electric field (E), electric drift velocity (Vd), momentum transfer collision frequency ( ), energy exchange collision frequency ( ) and characteristic energy (D/).The following physical quantities are deduced as function s E/P: mean free path of the electrons at unit pressure, mean energy lost by an electron per collision, mean velocity of agitation and the collisional cross-section of the molecules. The results are presented graphically and in tabular form. This results appeared a good agreement with the experimental data.

تم في هذا العمل حساب انتشار الإلكترونات واطئة الطاقة في غازات طبقات الجو، مثلاً (مزيج من غاز الآركون – الهيدروجين، غاز النيتروجين ومزيج من غاز الآركون – الهيليوم – النيتروجين) بوجود المجال الكهربائي وعند درجة حرارة 300 كلفن. قادت هذه الحسابات الى إيجاد قيمة طاقة تاون سيند بوصفها دالة لـ E/P (شدة المجال الكهربائي / ضغط الغاز)، شدة المجال الكهربائي، سرعة جرف الإلكترونات، تردد التصادم لانتقال الزخم، تردد التصادم لتبادل الطاقة والطاقة المميزة.تم اشتقاق الكميات الفيزياوية التي تم حسابها بوصفها دالة لـ E/P والتي تمثل أهم المعلمات الأساسية في دراسة غازات طبقات الجو وهي: معدل المسار الحر للإلكترونات بوحدة الضغط، معدل الطاقة المفقودة للإلكترون لكل تصادم، معدل سرعة التوهج والمقاطع العرضية التصادمية لجزيئات الوسط. هذه النتائج تم عرضها على شكل جداول وأشكال، إذ أظهرت تطابقاً مع النتائج العملية المنشورة


Article
Influence of Inter-Electrode Distance, Gas Mixing, Magnetic Field and Cathode Material on Breakdown Voltage of Lab-Made DC Magnetron Sputtering Device

Authors: Mohammed K. Khalaf --- Ibrahim R. Agool --- Shaimaa H. Abd Muslim
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2014 Volume: 10 Issue: 4 Pages: 21-25
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

In this paper, the effect of inter-electrode distance, gas mixing, magnetic field and cathode materials on breakdown voltage in DC glow discharge of argon and argon-oxygen plasma is presented. The results showed an increased breakdown voltage when inter-electrode distance and oxygen percentage in (Ar∕O2) gas mixture increased. At lower pressure, the breakdown voltage decreases by increasing the magnetic field, while at higher pressure, the breakdown voltage becomes less sensitive to the magnetic field. Moreover, the lower breakdown voltages are associated with smaller work function of the cathode material.


Article
Isentropic and Isenthalpic Cooling Techniques for Low-Temperature Discharges

Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2019 Volume: 15 Issue: 4 Pages: 29-32
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

In this article, the most common techniques used for the production of gas discharges at low temperatures are introduced. These techniques are mainly based on the isentropic and isenthalpic cooling processes of gases inside reactors known as liquefiers. The theoretical liquefaction efficiency of the helium was determined according to the physical data of this gas. Such determination can be extended to other inert gases used for generation of discharge plasmas, such as argon and neon as well as those gases usually used as reactive in plasma processing techniques, such as hydrogen, nitrogen and oxygen.


Article
Profile Optimization of the Discharge Electrodes in TEA CO2 Laser System
امثلية المظهر الجانبي لأقطاب التفريغ الكهربائي لليزر ثنائي اوكسيد الكاربون المستعرض المثار

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Abstract

In this work, four profiles (Chang, modified Chang, Ernst 4th order and Ernst 8th order) were considered to fabricate discharge electrodes of a TEA-CO2 laser from SiC composite. These four profiles were studied and simulated to optimize the distribution of electric field intensity on the electrode surface. As the profile of discharge electrode determines the uniformity of electric field over the whole discharge volume, it was considered experimentally as a reference to choose the best profile. Results show that Ernst 8th order profile is the best among the all simulated and tested profiles. This study may assist the designers of CO2, Excimer and N2 gas lasers to optimize the laser system during the designing course by adopting the most efficient profile of the discharge electrodes.

تم في هذا العمل اعتماد اربع مظاهر جانبية (اقطاب نوع تشانغ وتشانغ المعدلة وقطب ارسنت للمرتبة الرابعة الثامنة) لتصنيع اقطاب التفريغ الكهربائي لمنظومة ليزر ثنائي اوكسيد الكاربون ذات التهيج المستعرض عند الضغط الجوي TEA-CO2 Laser من مادة كربيد السيليكون. تم دراسة المظهر الجانبي لهذه الاقطاب ونمذجتها ومن خلال انتظام توزيع كثافة المجال الكهربائي على سطح القطب عمليا تم تحديد افضل مظهر جانبي للاقطاب الاربعة وتم مطابقة هذه النتائج العملية مع النتائج النظرية. اظهرت النتائج ان شكل قطب ارسنت للمرتبة الثامنة هو الافضل من بين النماذج المقاسة والتي قد اختبرت نظريا. ان هذه الدراسة ربما تساعد المصممين لليزرات الغازية (كليزر غاز ثنائي اوكسيد الكاربون و غاز النيتروجين والاكسايمر) في تحديد المظهر الامثل لشكل القطب وتحسينها أثناء التصميم من خلال اعتماد المنظر الجانبي الأكثر كفاءة من أقطاب التفريغ.

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