This paper investigates the characteristics some of argon plasma parameters of glow discharge under axial magnetic field. The DC power supply of range (0-6000) V is used as a breakdown voltage to obtain the discharge of argon gas. The discharge voltagecurrent (V-I) characteristic curves and Paschen’s curves as well as the electrical conductivity were studied with the presents of magnetic field confinement at different gas pressures. The magnetic field up to 25 mT was obtained using four coils of radius 6 cm and 320 turn by passing A.C current up to 5 Amperes. Spectroscopic measurements are employed for purpose of estimating two main plasma parameters electron temperature (Te) and electron density (ne). Emission spectra from positive column (PC) zone of the discharge have been studies at different values of magnetic field and pressures at constant discharge currents of 1.5 mA. Electron temperature (Te) and its density are calculated from the ratio of the intensity of two emission lines of the same lower energy levels. Experimental results show the abnormal glow region characteristics (positive resistance). Breakdown voltage versus pressure curves near the curves of paschen and decrease as magnetic field increases due to magnetic field confinement of plasma charged particles. Also the electrical conductivity increases due to enhancing magnetic field at different gas pressures. Both temperature density of electron and the intensities of two selected emission lines decrease with increasing pressure due decreasing of mean free path of electron. Electron density increase according to enhancing magnetic field, while the intensity of emitting lines tends to decrease.

Hollow anode argon glow discharge plasma has been investigated experimentally at different argon gas pressure fromconstant discharge current. A sufficient high voltage has been applied among the electrodes to obtain breakdown. Firstly, we studied the influence of hollow anode diameter on the breakdown voltage and Paschens law. The inner diameters of hollow anodes used in our work were (10, 15, 20, 25, 30, 35, and 40) mm. Secondly under the same conditions we extended our study to measure some plasma parameters in the negative glow region using direct current argon glow discharge. The temperature and density of electrons in the negative glow were measured using double probes. From the (Ip-Vp) characteristics of double probes, we obtained plasma parameters by using computer MATLAB program. The results showed that the measured Pashence's curve closes to the well-known theoretical Pashence's law. The breakdown voltage and its minimum value decreased with increasing the hollow anode diameter. The Paschen’s curve became wide and shifted to lower pressure with increasing the diameter. The reduction area of hollow anode caused dens and luminous intensity of plasma to occur in the negative glow region. Increasing the diameter resulted in decreasing the temperature and density of electron

An experimental investigation of hollow anodeargon glow discharge plasma has been carried out at different argon gas pressure ranged from 2.2 × 10ିଶto 3mbar forconstant discharge current. The glow discharge usually obtained by applying a high voltage between the electrodes sufficient to occurring breakdown of argon gas and sustaining the discharge.The experiments were conducted firstly to measure the breakdown voltage and Paschenc's law under the influence of hollowanode depth.A constant cathode disc of radius 20mm as well as hollow anodes of constant inner diameter 20mm and depths of values (10, 15, 20, 25, 30, 35, and 40) mm have been taken into consideration.Secondly, the study has been extended to measure some plasma parameters in the negative glow region ofdirect current argon glow discharge under the same conditions. Electric probes and a computer MATLAB program are used to obtain the temperature and density of electrons in the negative glow region from the double probes (Ip-Vp) characteristic. It was found from the results that the measured Pashence's curve closes to the well-known theoretical Pashence's law. The voltage breakdown and its minimum breakdown voltage decrease due to increasing the depthof cylindrical hollow. Increasing the hollow anode depth, the Paschen’s curve is widening.A dens and luminous intensity of plasma occurs in the negative glow region due to reduction of hollow anode depth. Both electron temperature and density of electron are decreases due to increasing the depth.

The present study represents a review article and a complementary study to a published paper of direct current hot cathode and hollow anode argon glow discharge plasma at different pressures in the range 0.05 - 0.8 mbar. The glow discharge usually obtained by applying a high voltage between the electrodes sufficient to occurring breakdown of argon gas and sustaining the discharge. Additional estimation of some plasma parameters, ion temperature, degree of ionization and electron energy distribution function as well as some characteristics of glow discharge under the influence of pressure and filament current has been done. Plasma parameters have been calculated using single probe method at fixed discharge current Id=1.88mA and diameter of hollow anode. Furthermore a computer MATLAB program is applied for this purpose. Results show that the average discharge voltage increases while its average discharge current decreases according to the increasing of the filament current. On the Contrary the average discharge voltage decrease nearly exponentially whiles its average discharge current increases according to increasing of the gas pressure. Degree of ionization starts to increase from low pressure to medium and then tends to decrease toward high pressure investigated. However it starts to increase to maximum value at filament current 0.9A then tends to decrease at higher current and low pressure. While for high pressures there is no significance change. Ion temperature increases slowly with filament current up to 0.9A and then sharply increases to maximum value at 1.5A. But it decreases for pressures in the range 0.05 - 0.09 mbar and then increases with gas pressure. Electron energy distribution function (EEDFs) decrease according to increases filament current, however, it starts to increase from low pressure to maximum value at medium pressure then tends to increase according to further increases of pressure.

The present study reports the results of extracorporeal shock-wave lithotripsy treatment for renal and ureteral stones in Duhok city. The data were collected from the center of breakdown kidney stones in Duhok hospital. There were a total of 40 patients (25 males and 15 females) aged from 20 to 60 years old. The patients harboring (23 renal and 17 ureteral) stones of size ranged from 7.5 to 20 mm. Almost stones are of average size 9 mm and composed of uric acid, calcium and cystine stones. The study has been carried out by taking into consideration the parameters (type, sizes, composition and location of stone as well as region and ages of patients, also power, number of shock wave and sessions). The results show that the stones size increases according to increasing ages of patients (male and female) for uric acid ureter stone and calcium (renal, ureter) stones. Also (renal, ureter) stone size for patients aged from 20 to 30 years old increases from the minimum value for phosphate to maximum value for cystine stones, while for patients aged from 40 to 60 years old, the minimum size is obtained for calcium oxalate and the maximum size for calcium only. On the other hand, for uric acid stones of average size 9 mm, number of shock wave and sessions as well as the power required to breakdown the stones decrease nearly exponentially according to enhancing patients’ ages. At the same time, it's found that for adult patients (20 - 30 years old), number of sessions and the power of shock wave decrease also according to increasing size of calcium and cystine stones. Contrary to that, for the same ages and renal, uretral cysteine stones number of shock wave needed to breakdown large stones will be increased.

In the present study, investigation of extracorporeal shock wave lithotripsy in Zakho City for breakdown kidney and ureteral stones has been carried out. The data were collected from the center of breakdown kidney stones in Zakho hospital. A total of 34 patients (25 male and 9 female) of ages ranged from 20 - 60 years were treated with ESWL. The patient harboring 24 renal stones and 10 ureteral stones of size ranged from 7 to 23 mm of almost patients are 8 mm and composed of calcium oxalate. The study has been conducted taking in to consideration the parameters (type, sizes, composition and location of stone as well as region and ages of patients, also power, number of shock wave and session). The results show that the number of shock wave decreases nearly ex- ponentially with the ages of patients for calcium oxalate stone of size 8 mm under constant power 4 watt while it tends to increase according to increasing stones size for the patients of ages 20 - 30 years. The size of calcium oxalate stones decreases nearly exponentially with the patients’ ages for workers in Zakho city. Also for same size 8 mm of (calcium, phosphate, and oxalate) stones and different regions of zakho city, the number of shock waves decreases according to increasing ages of patients. Contrary to that for certain size of stones 8 mm, the number of shock wave starts to increase from uric acid to maximum value for calcium oxalate stone for the adult patients of age’s 22 up to 30 years. However for elders ages 30 - 60 years and different regions, the size of renal and ureteric stones increases from the minimum value for calcium, phosphate, oxalate to maximum value for calcium oxalate stone only. Uric acid stone requires minimum power to break, while the calcium oxalate needs maximum power to fragment due to its hardness composition. Later num- ber of session of shock wave required for crushing each stones size increases according to in- creasing its size while its variation due to enhancing patients ages for calcium oxalate of size 8 mm results in nearly a decreasing exponential behavior

Hot cathode and hollow anode argon DC glow discharge plasma at different pressures of (0.04, 0.05, 0.06, 0.07, 0.09, 0.2, 0.4, and 0.8 mbar) has been investigated. The experiments were carried out under the influence of pressure and filament cathode current on voltage – current characteristics of glow discharge and its breakdown voltage. Plasma parameters have been measured and obtained using single probe method at fixed discharge current (Id=1.88 mA) and hollow anode diameter. A computer MATLAB program is performed for this purpose. It was shown that the discharge voltage – current characteristics curve has a positive resistance and represents an abnormal glow region at pressure (0.04 and 0.06) mbar for different filament current. The breakdown voltage increases as the filament current is increased. In different pressure, electron temperature shows different behavior with increasing filament current. Electron density varies nearly inversely with the filament current, but it is increase due to increase of pressure from (1 to 3 mbar), then tends to decrease for the higher pressure. There are two groups of electrons according to the two peaks of (EEDFs), and the peaks amplitude decrease, with the increases of both filament current and gas pressure.

An experimental study of DC hollow cathode glow discharge plasma at different nitrogen pressures ranged from (0.015 to 0.75Torr) has been proposed.Investigated was carried out under the influence of the hollow cathode geometry such as diameter and depth of hollow cathode at fixed discharge current (I d =1.88 mA). Langmuir double probe method has been used to measure and calculate the plasma parameters as well as a computer MATLAB program is performed for this purpose. The results shows that the electron temperature increased with the increasing both inter-cathode distance and depth of hollow cathode for the low range of pressure (0.015, 0.038, 0.06) torr, while this behavior is inversed in high pressure ranges (0.15, 0.375, 0.6, 0.75) torr, due to the hollow cathode effect. Electron density tends to increase by decreasing hollow cathode geometry. On the other hand both floating and plasma potential increases with the increasing geometrical factor. It's observed that the results have satisfactory agreement with previous work reported in this field of hollow cathode.

The paper investigates the luminous intensity emitted from dc hollow cathode glow discharge plasma (HCGD) .The experiments were conducted at different nitrogen gas pressures ranged from (0.015 to 0.75Torr) and constant discharge current (Id=1.88 mA).The influence of both pressure and hollow cathode geometry such as diameter and depth of hollow cathode have been studied .The results show that the Photo-Luminous Efficiency emitted from the hollow cathode glow discharge decrease nearly exponentially with the increasing gas pressure. This is due to the characteristics of hollow cathode at the low pressures to produce more energetic excitation. On the other hand, the luminous efficiency increase linearly with the increasing inter-cathode distance of hollow, this is because increasing the inter - cathode distance of hollow cathode is equivalent to the decreasing of gas pressure. However the luminous intensity increase linearly with the depth of hollow cathode ranged from (1up to2.5) cm and then decrease. This behavior of the intensity with both the gas pressure and hollow cathode geometry is satisfactory agreement with previous works.

An experimental investigation of a DC hollow cathode nitrogen glow discharge has been done at different gas pressure ranged from (0.075 to 0.75) torr and different radial positions of discharge. Plasma properties were inferred from the current – voltage characteristics of the double probes positioned at different radial space of the discharge, moreover a computer program proposed to determine plasma parameters from the probe characteristics. Furthermore these parameters were calculated using the relation that electron temperature can be written as an explicit function of gas pressure and radius discharge at the Schottky limit. The result exhibits that the measured and calculated electron temperature varies nearly a decreasing exponential with gas pressure as a results of fitting , as well as the variations of both floating and plasma potentials close to the same behavior. On the other hand there is a good agreement between measured and calculated results, these in turn compared with reported works in previous studies and there is a satisfactory agreement

The magnetic pressure, plasma pressure and the ratio between them which represent the beta (b) have been determined in a D.C electric arc discharge for current values (3.5-24A) under argon gas pressure ranged from (0.1-50torr). The obtained electron density and temperature from the double probes characteristic were used to calculate the magnetic and plasma pressure as well as the beta. The electron temperature explicit relation of product of gas pressure and radius of discharge arc that holds