Experimental study of impedance characteristics in pulsed electrical discharges

العناوين الأخرى

دراسة تجريبية لخصائص الممانعة للتفريغ الكهربائي النبضي

مقدم أطروحة جامعية

al-Rashidi, Ala Fadil Ahmad

مشرف أطروحة جامعية

Hassani, Abd al-Rida Salman

أعضاء اللجنة

al-Amidy, Dhia H.
Suhayl, Abd Allah Muhsin
Khamis, Rad Azzawi
Husayn, Ali Abd al-Karim
Iltaif, Abd al-Husayn Khudayr

الجامعة

جامعة بغداد

الكلية

كلية العلوم

القسم الأكاديمي

قسم الفيزياء

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2011

الملخص الإنجليزي

A number of pulsed experiments has been carried out using a high-voltage circuit containing R, L and C in certain arrangements.

Three configurations (spherical, rod-sphere and cylindrically-tipped) of the spark gap electrodes, which were made of either steel or copper, have been used as a high-current switch operated by a voltage of up to 8 kV and triggered in both self- and a third-electrode modes.

Current measurements are carried out using both currentviewing resistors and Rogowski coils designed and constructed for this purpose.

Typical current waveforms have shown obvious dominating inductance effect of the circuit components in an underdamped oscillation.

The behavior of the circuit impedance is studied by recording both pulsed current peaks and charging voltages when currents of up to 4.5 kA are recorded.

The duration of these current pulses are found to extend between 0.1 μs and 0.3μs depending on the values of the circuit components as well as the spacing of the spark gap electrodes along which the plasma propagates with certain speeds of an average value of 5.6 m ms-1 at atmospheric pressure.

Over the whole range of experimental conditions, the average nominal impedance values ranged between 2 Ω and 30 Ω depending on the gap and circuit parameters.

Typical damage patterns were observed in the spherical electrodes with average diameters of up to 8.3 mm on the high voltage electrode and 10.5 mm on the grounded sphere resulting from accumulative discharges and power dissipation within the gap.

Results of the three spark gap configuration were compared with each other to establish an optimum conditions and parameters, which were capable of imposing such features on all experiments.The application of an external longitudinal magnetic field (27G) on the cylindrically-tipped electrodes showed a slight change in the discharge voltage and an alteration in the discharge current density due to physical effects including lateral diffusion of electrons and their energy over successive collisions.

التخصصات الرئيسية

الفيزياء

عدد الصفحات

140

قائمة المحتويات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-606165