Electric field and ionization waves in Pulsed Atmospheric Plasma Streams (PAPS): complementary in situ diagnostics

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Electric field and ionization waves in Pulsed

Atmospheric Plasma Streams (PAPS): complementary in situ diagnostics

Sylvain Iséni, X Damany, G Sretenović, V Kovačević, I Krstić, S Dozias, J.-M Pouvesle, M Kuraica, E Robert

To cite this version:

Sylvain Iséni, X Damany, G Sretenović, V Kovačević, I Krstić, et al.. Electric field and ionization waves in Pulsed Atmospheric Plasma Streams (PAPS): complementary in situ diagnostics. 6th International Conference on Plasma Medicine (ICPM-6), Sep 2016, Bratislava, Slovakia. 2016. �hal-01670162�

(2)

Electric field and ionization waves in Pulsed Atmospheric Plasma Streams (PAPS):

complementary in situ diagnostics

S. Iséni ¹ , X. Damany ¹ , G. Sretenović ² , V. Kovaˇcević ² , I. Krstić ² , S. Dozias ¹ , J.-M. Pouvesle ¹ , M. Kuraica ² and E. Robert ¹

1 GREMI – UMR 7344, CNRS/Universit´e d’Orl´eans, FRANCE

2 Laboratory of Physics and Technology of Plasma – University of Belgrade, SERBIA

PHC Pavle Savic 2016 - #36216UA

Introduction and motivation

In this study, one focuses on the diagnostic of single pulsed atmospheric

plasma streams (PAPS) with the investigation of electric field (E-field) [1].

Experimental E-field characterizations are extremely beneficial for the

comprehension of plasma mechanisms and particularly for the validation of numerical simulations. The authors present the results of strength E-field obtained with two different methods:

I The first technique is a custom made electro-optic sensor based on the Pockels effect [2], allowing for recording simultaneously two orthogonal components of the E-field vector, time and spaced resolved [1].

I The second method uses Stark polarization dependent emission spectroscopy of the –weak– He I line at 492.19 nm [3].

Depending on the experimental conditions, both methods will be either complementary or compared with each other. The outcomes will bring

information about the reliability of each technique and are of high interest for the validation of numerical simulation results.

Plasma source: Plasma Gun (PG)

grounded electrode

inlet Helium gas flow H.V. hollow

inner electrode

dielectric capillary

-

+

ON/OFF

µs H.V. pulse generator

100mm

10 to 30mm 4mm

target

PAPS

gas flow

Operating features:

I kHz pulsed µ s H.V. driver, . 8 kV to 20 kV

. 1 kHz to 4 kHz

I Glass or quartz capillary (100 mm) long,

I Powered inner hollow electrode, I Grounded outer electrode,

I Polarity: positive or negative,

I Buffer gas: helium / neon / argon . 50 sccm to 5 × 10

³

sccm

Electric field diagnostic at GREMI – electro-optic probe

I Electro-optic sensor . Pockels effect

. BSO crystal

I crystal

= 1.8 mm, 1.0 mm long

I probe

= 4.0 mm – alumina I Transient E-field

. 50 kHz to 1 GHz

. 10 V · cm

⁻¹

to 100 kV · cm

⁻¹

I 2 orthogonal components simultaneously . k E ~ k = p

|E

_x

|

²

+ |E

_r

|

²

I Absolute E-field strength

Analyzing unit, eoSense

^tm

.

Electro-optic probe.

Electric field diagnostic at LPTP – π-polarization Stark He I

I Optical emission spectroscopy technique – non-intrusive method,

I π-polarization Stark ⇒ splitting and shifting of the allowed and forbidden counterpart transitions of He I (492.19 nm) depend on the light polarization, I Time and space resolved,

I 1 E-field component,

I Absolute E-field strength ( ' 4 kV · cm

⁻¹

).

-

+

ON/OFF

1m spectrometer 1200/2400 gr/mm iCCD achroma

f=150mm linear polarizer

slit: 70µm He HV pulsed

generator

Experimental setup. Typical π-polarized spectra of the He I in a plasma jet [4].

Evidence of the ionization front

The ionization wave allowing for the ignition of atmospheric pressure

plasma jets operating in the kHz regime are often reported as plasma bullet.

This phenomenological description accounts only for the light emission of the ionization front. The graph bellow presents the inception of the

discharge and evidences the fast rise of E ~

_x

then followed by E ~

_r

[1].

Time evolution of the ionization front.

I Establishment of E ~

_x

about 500 ns before the emission of the light, I k E ~ k is in the order of 10 kV · cm

⁻¹

to 20 kV · cm

⁻¹

[4].

Comparison with numerical simulation results

Time evolutions of the E ~

_x

and E ~

_r

of the E-field, fig. 16 [5].

E ~

_x

of the E-field computed and

measured by π -polarization Stark He I.

E-field measurement within the plasma plume

EO probealumi glass tube plasma plume na

axial distance / mm longitudinal distance (mm)

5 0 15 10 25 20

radial distance (mm) 0 5 10 15 20 25 30 35 40 E field (kV/cm)

10 20 30 40 50

0 5 10 15 20 25 30 35 40 45

longitudinal distance (mm) 5 0 15 10 25 20 radial distance (mm)

0 5 10 15 20 25

30 35 40 E field (kV/cm)

1 2 3 4 5 6 7

0.8 1.6 2.4 3.2 4.0 4.8 5.6

E-field values obtained by π-polarization Stark

He I.

k E ~ k 2D scan performed by the electro-optic

probe.

E ~

_r

2D scan performed by the electro-optic

probe.

I Both techniques show an increase of the E-field within the plasma plume, I E ~

_r

resembles the ring-shape structure also reported in [4].

Concluding remarks

I E-field characterization is the method of choice to study ionization waves, I Both techniques produce results in agreement with numerical simulations, I The complementarity of the methods are demonstrated.

References

[1] Robert, E., Darny, T., Dozias, S., Iseni, S., and Pouvesle, J. M. Physics of Plasmas 22(12), 122007 dec (2015).

[2] Gaborit, G., Jarrige, P., Lecoche, F., Dahdah, J., Duraz, E., Volat, C., and Duvillaret, L. IEEE Trans. Plasma Sci. 42(5), 1265–1273 may (2014).

[3] Kuraica, M. M. and Konjevi´c, N. Appl. Phys. Lett. 70(12), 1521 (1997).

[4] Sretenović, G. B., Krstić, I. B., Kovaˇcević, V. V., Obradović, B. M., and Kuraica, M. M. Journal of Physics D:

Applied Physics 47(10), 102001 (2014).

[5] Bourdon, A., Darny, T., Pechereau, F., Pouvesle, J.-M., Viegas, P., Is´eni, S., and Robert, E. Plasma Sources Sci. Technol. 25(3), 035002 mar (2016).

Created with L^ATEXbeamerposter http://www-i6.informatik.rwth-aachen.de/~dreuw/latexbeamerposter.php

Electric field and ionization waves in Pulsed Atmospheric Plasma Streams (PAPS): complementary in situ diagnostics

Electric field and ionization waves in Pulsed Atmospheric Plasma Streams (PAPS):

complementary in situ diagnostics

S. Iséni 1 , X. Damany 1 , G. Sretenović 2 , V. Kovaˇcević 2 , I. Krstić 2 , S. Dozias 1 , J.-M. Pouvesle 1 , M. Kuraica 2 and E. Robert 1

1 GREMI – UMR 7344, CNRS/Universit´e d’Orl´eans, FRANCE

2 Laboratory of Physics and Technology of Plasma – University of Belgrade, SERBIA

Introduction and motivation

In this study, one focuses on the diagnostic of single pulsed atmospheric

plasma streams (PAPS) with the investigation of electric field (E-field) [1].

Experimental E-field characterizations are extremely beneficial for the

comprehension of plasma mechanisms and particularly for the validation of numerical simulations. The authors present the results of strength E-field obtained with two different methods:

I The first technique is a custom made electro-optic sensor based on the Pockels effect [2], allowing for recording simultaneously two orthogonal components of the E-field vector, time and spaced resolved [1].

I The second method uses Stark polarization dependent emission spectroscopy of the –weak– He I line at 492.19 nm [3].

Depending on the experimental conditions, both methods will be either complementary or compared with each other. The outcomes will bring

information about the reliability of each technique and are of high interest for the validation of numerical simulation results.

Plasma source: Plasma Gun (PG)

grounded electrode

inlet Helium gas flow H.V. hollow

inner electrode

dielectric capillary

µs H.V. pulse generator

100mm

10 to 30mm 4mm

target

PAPS

gas flow

Operating features:

I kHz pulsed µ s H.V. driver, . 8 kV to 20 kV

. 1 kHz to 4 kHz

I Glass or quartz capillary (100 mm) long,

I Powered inner hollow electrode, I Grounded outer electrode,

I Polarity: positive or negative,

I Buffer gas: helium / neon / argon . 50 sccm to 5 × 10

sccm

Electric field diagnostic at GREMI – electro-optic probe

I Electro-optic sensor . Pockels effect

. BSO crystal

= 1.8 mm, 1.0 mm long

= 4.0 mm – alumina I Transient E-field

. 50 kHz to 1 GHz

. 10 V · cm

to 100 kV · cm

I 2 orthogonal components simultaneously . k E ~ k = p

|E

|

+ |E

|

I Absolute E-field strength

Analyzing unit, eoSense

.

Electro-optic probe.

Electric field diagnostic at LPTP – π-polarization Stark He I

I Optical emission spectroscopy technique – non-intrusive method,

I π-polarization Stark ⇒ splitting and shifting of the allowed and forbidden counterpart transitions of He I (492.19 nm) depend on the light polarization, I Time and space resolved,

I 1 E-field component,

I Absolute E-field strength ( ' 4 kV · cm

).

Experimental setup. Typical π-polarized spectra of the He I in a plasma jet [4].

Evidence of the ionization front

The ionization wave allowing for the ignition of atmospheric pressure

plasma jets operating in the kHz regime are often reported as plasma bullet.

This phenomenological description accounts only for the light emission of the ionization front. The graph bellow presents the inception of the

discharge and evidences the fast rise of E ~

then followed by E ~

[1].

Time evolution of the ionization front.

I Establishment of E ~

about 500 ns before the emission of the light, I k E ~ k is in the order of 10 kV · cm

to 20 kV · cm

[4].

Comparison with numerical simulation results

Time evolutions of the E ~

and E ~

of the E-field, fig. 16 [5].

E ~

of the E-field computed and

measured by π -polarization Stark He I.

E-field measurement within the plasma plume

E-field values obtained by π-polarization Stark

He I.

S. Iséni ¹ , X. Damany ¹ , G. Sretenović ² , V. Kovaˇcević ² , I. Krstić ² , S. Dozias ¹ , J.-M. Pouvesle ¹ , M. Kuraica ² and E. Robert ¹