Monte Carlo simulation of the cathode fall region of a CO<sub>2</sub> laser glow discharge for studying the influence of magnetic fields on instability growth

R. Razdan; C. E. Capjack; H. J. J. Seguin

doi:10.1364/AO.25.002915

Applied Optics
Vol. 25,
Issue 17,
pp. 2915-2925
(1986)
•https://doi.org/10.1364/AO.25.002915

Monte Carlo simulation of the cathode fall region of a CO₂ laser glow discharge for studying the influence of magnetic fields on instability growth

R. Razdan, C. E. Capjack, and H. J. J. Seguin

Not Accessible

Your library or personal account may give you access

Get PDF
Email
Share
Get Citation
Copy Citation Text
R. Razdan, C. E. Capjack, and H. J. J. Seguin, "Monte Carlo simulation of the cathode fall region of a CO₂ laser glow discharge for studying the influence of magnetic fields on instability growth," Appl. Opt. 25, 2915-2925 (1986)

Export Citation
- BibTex
- Endnote (RIS)
- HTML
- Plain Text
Citation alert
Save article

Abstract

It has been shown experimentally that properly profiled magnetic fields can be used to enhance the stability of CO₂ laser gas discharges [ C. E. Capjack, et al., J. Appl. Phys. 52, 4517 ( 1981); H. J. J. Seguin, et al., Appl. Phys. Lett. 39, 203( 1981)]. Initially, the mechanism of stabilization was thought to be due to bulk motion of the gas molecules due to collisions with ions drifting in the E × B direction. Computational analysis, however, has subsequently shown that the primary stabilization mechanism involves the dispersion of localized charged particle perturbations over the cathode electrode surface area in a time interval less than that required for an instability to develop. In an earlier paper [ R. Razdan, et al., J. Appl. Phys. 57, 4954 ( 1985)], the present authors used a Monte Carlo simulation technique to analyze the cathode fall region of a helium gas discharge. The theoretical data showed the effect of a varying magnetic field on stability. In this paper, the results have been extended to the other gases of interest in CO₂ lasers, principally N₂ and CO₂. In addition, a typical CO₂ laser gas discharge containing a mixture of He, N₂, and CO₂ in a 20:8:2-Torr ratio has been analyzed. The results confirm that the use of magnetic fields in the vicinity of the cathode surface can indeed enhance the stability of a CO₂ laser gas discharge, thereby providing the potential for increasing its power output.

Full Article | PDF Article

More Like This

Electrical characteristics of a MAGPIE coaxial laser discharge system

V. A. Seguin, H. J. J. Seguin, and C. E. Capjack
Appl. Opt. 24(9) 1265-1269 (1985)

Anomalous refractive indices of the amplifying medium in a waveguide CO₂ laser

Tomizo Kurosawa
Appl. Opt. 25(21) 3816-3824 (1986)

Multiple pass unstable resonator for an annular gain CO₂ laser

V. A. Seguin, H. J. J. Seguin, C. E. Capjack, S. K. Nikumb, and H. Reshef
Appl. Opt. 25(21) 3825-3829 (1986)

Previous Article Next Article

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Figures (4)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Tables (5)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Equations (6)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

(a) HELIUM

Type of Cross-Section	Onset Energy (eV)	Reference	Range of Application (eV)

Total Scattering	0	Andrick & Bitsch12	1.0 − 20
Total Scattering	0	de Heer & Jansen13	20 − 500

Triplet Excitation (2³s + 2¹s)	19.805	Fleming & Higginson	19 − 30
Triplet Excitation (2³s + 2¹s)	19.805	de Heer & Jansen	30 − 1000

Excitation (2¹p) (Level 2)	21.203	de Heer & Jansen13	30 − 500

Ionization	24.586	Rapp & Englander-Golden15	24 − 500

Differential Excitation	--	Shyn16	2, 3, 5, 10, 15, 20, 30, 40, 50, 70, 100

(b) NITROGEN
Total Scattering	0	Golden17	0.36–4.4
Total Scattering	0	Shyn et al.18	5.0–90
Vibrational Excitation (Level 1)	.291, .582, .873, 1.46, 1.75, 2.04, 2.33	Engel hardt et al19	0 − 3
Excitation (Levels 2–5)	6.22, 7.39, 8.59, 11.05	Engelhardt et al19	6.22-100
Ionization	15.7	Rapp & Englander–Golden15	15.7–100
Dissociative Ionization (Level 6)	25.5	Rapp & Englander–Golden15	25.5–100
Differential	----	Shyn et al16	1.5, 1.9, 2.1, 2.4, 3, 4, 5, 7, 10, 15, 20, 30, 40, 50, 70, 100

(c) CARBON-DIOXIDE
Total Scattering	0	Ramsauer & Kollath20	0.14–2.7
Total Scattering	0	Bruche21	2.9–100

Vibrational Excitation (Level 1)	.0827, 0.291, 0.580, 0.870	Hake & Phelps22	0 − 100

Excitations (Levels 2,4,5)	3.1	Hake & Phelps22	3 − 100
	7.0
	10.0

Dissociation (Levels 3,6)	6.1	Corvin & Corrigan23	6 − 100
Dissociation (Levels 3,6)	11.5	Ajello24	11 − 100

Ionization	13.3	Rapp & Englander–Golden15	13 − 100

Dissociation Ionization (Level 7)	25.0	Rapp & Englander–Golden15	25 − 100

Differential Elastic Scattering	--	Shyn et al25	3, 4, 5, 7, 10, 15, 20, 30, 40, 50, 70, 90

(i) 5 Torr (d_c = 2.6 mm.)

Mag. Field (Gauss)	Total No. of Coils.	Hall Parameter	Distribution of collision types (Percentage)				Avg. Dist. Y(× d)	Avg. Energy (eV)	Avg. transit time (ns)	Discharge Velocity (m/s)
Mag. Field (Gauss)	Total No. of Coils.	Hall Parameter	Elastic	Level 1	Level 2	Ionisation	Avg. Dist. Y(× d)	Avg. Energy (eV)	Avg. transit time (ns)	Discharge Velocity (m/s)

1	53.50	0.00108	95.665	0.176	1.923	2.236	0.005	19.19	8.736	−65.75

500	68.92	0.55160	96.464	0.191	1.582	1.763	0.481	18.52	12.20	6415

1000	111.90	1.17400	97.714	0.161	1.035	1.090	0.942	16.35	22.040	12450

(ii) 10 Torr (d_c = 1.3 mm.)
1	54.11	0.00054	95.679	0.189	1.946	2.186	−0.002	19.49	4.428	−34.47
500	57.57	0.27137	95.853	0.187	1.894	2.066	0.231	19.13	4.746	5767
1000	68.75	0.55130	96.471	0.171	1.604	1.753	0.469	18.54	6.036	11250

(iii) 30 Torr (d_c = 0.43 mm.)
1	54.05	0.00018	95.642	0.185	1.975	2.198	0.008	19.50	1.468	−10.3
500	54.72	0.08976	95.720	0.191	1.914	2.175	0.077	19.42	1.505	3857.4
1000	55.92	0.17918	95.754	0.193	1.911	2.141	0.150	19.50	1.529	8020.7

(i) 5 Torr (d_c = 8.4 mm.)

Mag. Field (Gauss)	Total No. of Colls.	Hall Parameter	Distribution of collision types (Percentage)								Avg. Dist. Y (× d)	Avg. Energy (eV)	Avg. transit time (ns)	Discharge Vel. (m/s)
Mag. Field (Gauss)	Total No. of Colls.	Hall Parameter	Elastic	1	2	3	4	5	6	Ionisation	Avg. Dist. Y (× d)	Avg. Energy (eV)	Avg. transit time (ns)	Discharge Vel. (m/s)

1	805.4	0.0012	96.72	0.993	0.447	1.440	0.174	0.199	0.0	0.0261	−0.0198	2.0022	59.52	−0.01

500	1063.0	0.5347	97.10	0.978	0.395	1.204	0.113	0.188	0.0	0.0198	0.4006	2.2496	88.07	910.1

1000	1389.0	1.1188	97.90	0.864	0.288	0.792	0.072	0.072	0.0	0.0083	0.7268	2.0511	136.82	1860.1

(ii) 10 Torr (d_c = 4.2 mm.)
1.0	921.85	0.00053	96.48	1.044	0.514	1.476	0.208	0.254	0.02252	−0.005	2.3340	34.56	14.39
500	807.18	0.30193	96.62	1.044	0.483	1.410	0.181	0.246	0.01892	0.168	1.9436	30.75	901.2
1000	960.78	0.59050	96.93	0.998	0.446	1.235	0.167	0.212	0.01504	0.359	1.9653	39.89	1727.6

(iii) 30 Torr (d_c = 1.4 mm.)
1.0	887.20	0.00018	96.70	1.014	0.451	1.443	0.135	0.225	0.02590	−0.007	2.3356	11.11	0.00
500	838.60	0.09639	96.75	1.026	.0.429	1.407	0.143	0.215	0.02726	0.056	2.0671	10.26	744.3
1000	829.80	0.19220	96.72	1.012	0.434	1.422	0.169	0.217	0.02426	0.133	2.0586	10.25	1495.3

(ii) 10 Torr (d = 4.0 mm.)
1.0	1345	0.0003	95.41	2.352	0.392	0.188	0.298	0.935	0.229	0.1993	−0.003	2.466	95.30	0.0
500	1356	0.1707	95.42	2.363	0.399	0.189	0.289	0.916	0.223	0.1971	0.097	2.448	94.06	268.5
1000	1417	0.3379	95.44	2.409	0.392	0.181	0.284	0.889	0.217	0.1874	0.199	2.498	.97.91	602.6

(iii) 30 Torr (d = 1.33 mm.)
1.0	1345	0.0001	95.42	2.354	0.392	0.188	0.296	0.926	0.229	0.1974	−0.001	2.473	31.24	0.058
500	1346	0.0571	95.42	2.346	0.392	0.190	0.295	0.924	0.229	0.1993	0.032	2.433	31.75	173.9
1000	1352	0.1126	95.41	2.359	0.397	0.188	0.295	0.922	0.228	0.1964	0.064	2.500	31.43	401.1

Mag. Field (Gauss)	Total No. of Colls.	Total No. of Colls. types			Hall Parameter	Distribution of collision types (Percentage)									Avg. Dist. Y (× d)	Avg. Energy (eV)	Avg. transit time (ns)	Discharge Vel. (m/s)
		Total No. of Colls. types				HELIUM			NITROGEN			CARBON–DIOXIDE
		He	N2	CO2		Elastic	Tot. Exct.	Ionisat.	Elastic	Tot. Exct.	Ionisat.	Elastic	Tot. Exct.	Ionisat.

1	221	114	49	58	0.0002	99.48	0.298	0.223	88.95	10.01	0.968	92.31	6.394	1.295	0.0017	4.901	6.526	0.0

100	220	113	49	58	0.0205	99.47	0.309	0.218	88.98	10.05	0.974	92.21	6.543	1.247	0.0116	4.869	6.398	45.0

500	219	112	49	58	0.1023	99.48	0.304	0.220	88.89	10.13	0.982	92.28	6.477	1.241	0.0634	4.860	6.374	250.8

1000	224	115	50	59	0.2055	99.48	0.306	0.216	89.12	9.902	0.973	92.33	6.454	1.217	0.1351	4.821	6.610	512.0

Abstract

Cited By

Figures (4)

Tables (5)

Equations (6)

Applied Optics