INFINA (EX INFIP) 05545

INSTITUTO DE FISICA INTERDISCIPLINARIA Y APLICADA

Unidad Ejecutora - UE

artículos

Título:

On the use of the metallic nozzle of a cutting arc torch as a Langmuir probe

Autor/es:

PREVOSTO, LEANDRO; MANCINELLI ,BEATRIZ; KELLY, HÉCTOR

Revista:

PHYSICA SCRIPTA

Editorial:

IOP

Referencias:

Año: 2008 vol. T131 p. 14026 - 14030

ISSN:

0031 8949

Resumen:

The region inside the nozzle (bore diameter 1 mm) of a cutting arc torch is inaccessible to
most plasma diagnostics, and numerical simulations are the only means to find out the relative
importance of several physical processes. In this work, a study of electrostatic (Langmuir)
probes applied to the inside of a high energy density 30A cutting arc torch nozzle is presented.
The metallic nozzle was used as a Langmuir probe, so the plasma flow is not perturbed by the
probe as a solid body. Biasing the nozzle through an electric circuit that employs appropriate
resistors together with the arc power source, the iV nozzle characteristic was built. It was
found that under a large positively biased nozzle, the electron current drained from the arc was
relatively small, 1 A, notwithstanding the fact that the size of the nozzle was relatively large.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
found that under a large positively biased nozzle, the electron current drained from the arc was
relatively small, 1 A, notwithstanding the fact that the size of the nozzle was relatively large.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
most plasma diagnostics, and numerical simulations are the only means to find out the relative
importance of several physical processes. In this work, a study of electrostatic (Langmuir)
probes applied to the inside of a high energy density 30A cutting arc torch nozzle is presented.
The metallic nozzle was used as a Langmuir probe, so the plasma flow is not perturbed by the
probe as a solid body. Biasing the nozzle through an electric circuit that employs appropriate
resistors together with the arc power source, the iV nozzle characteristic was built. It was
found that under a large positively biased nozzle, the electron current drained from the arc was
relatively small, 1 A, notwithstanding the fact that the size of the nozzle was relatively large.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
found that under a large positively biased nozzle, the electron current drained from the arc was
relatively small, 1 A, notwithstanding the fact that the size of the nozzle was relatively large.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
1 mm) of a cutting arc torch is inaccessible to
most plasma diagnostics, and numerical simulations are the only means to find out the relative
importance of several physical processes. In this work, a study of electrostatic (Langmuir)
probes applied to the inside of a high energy density 30A cutting arc torch nozzle is presented.
The metallic nozzle was used as a Langmuir probe, so the plasma flow is not perturbed by the
probe as a solid body. Biasing the nozzle through an electric circuit that employs appropriate
resistors together with the arc power source, the iV nozzle characteristic was built. It was
found that under a large positively biased nozzle, the electron current drained from the arc was
relatively small, 1 A, notwithstanding the fact that the size of the nozzle was relatively large.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
found that under a large positively biased nozzle, the electron current drained from the arc was
relatively small, 1 A, notwithstanding the fact that the size of the nozzle was relatively large.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
iV nozzle characteristic was built. It was
found that under a large positively biased nozzle, the electron current drained from the arc was
relatively small, 1 A, notwithstanding the fact that the size of the nozzle was relatively large.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.
1 A, notwithstanding the fact that the size of the nozzle was relatively large.
On the other hand, an almost linear ion current was found for the ion branch for nozzle
voltages well below the floating value. Based on the magnitude of inverse slope of the ion
current, an estimation of the average electron temperature of the plasma in the vicinity of the
nozzle wall was estimated from an ion sheath resistance model using a non-equilibrium
two-temperature Saha-equation. An average electron temperature of about 4200K and a
corresponding plasma density of 4×1017 m−3 were found.×1017 m−3 were found.