R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 1
Masaryk University Brno
Department of Physical Electronics
Atmospheric Pressure Plasmas –
Basics and Applications
Ronny Brandenburg
Lecture II: Diagnostics of non-thermal atmospheric pressure plasmas
– Electrical characterization
– Optical emission spectroscopy, fast optical/spectroscopic methods
– Surface charge measurements
“Macroscopic” diagnostic
… to be performed AT LEAST on reactors
Electrical characterization
- Voltage and current oscillography
- Power measurements Specific Energy Density
Gas analysis (chemistry)
- Flame Ionization Detection (FID): Total hydrocarbons (THC)
- Fourier transform infrared spectroscopy (FTIR): IR-active species
- Gas Chromatography – Mass Spectrometry (GC-MS)
… and if possible
Optical and spectroscopic methods
- Optical emission spectroscopy: indirect and average information!
- Fast imaging: Distribution of MDs local power density
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 2
Electrical characterization of DBDs
Equivalent circuit (the simplest!)
Electrical characterization of DBDs
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 3
Optical emission spectroscopy
• Simple, non-intrusive
• Emission of plasma (indirect
information)
gas/excitation temp.
electrons (Stark tech.)
• Monitoring of processes
intensity
spectrum performance
Filamentary plasmas
2 mm
Electrical breakdown in several individual ionization channels
Filaments = repetitive, but transient Microdischarges (MDs)
6 mm
4 mm
Volume Barrier Discharge (air)
Surf ace Barrier Discharge (air)
Plasma jet (Ar)
Atmospheric pressure
high collision rates (rapid ionization, quenching)
streamer breakdown mechanism favoured (Raether/Meek criterion)
small dimensions (Paschen law)
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 4
Discharge physics and plasma chemistry
Plasma-CHEMISTRY
Electric
Field
Breakdown
Electrons
& Ions
Excited
Species
Chemical
Reactions
Heat and
Mass
Transfer
Discharge-PHYSICSTimescales
10-12 s ...
10-9 s ...
10-6 s ...
10-3 s
10-3 s ...
101 s
Plasma parameters (E/n, ne)
Densities of active species (nX, n+, n-)
Excitation and relaxation processes
Yield of (by-)products
Efficiency of decomposition etc.
MDs as
„tiny chemical reactors“
MD-multitude determines
overall chemistry
The challenge
Small scale (diameter, discharge gap) 10 µm … 5 mm
Transient and short lived 10 ns … 1 µs
Erratic appearing Triggering ?
Low emission intensity Spectral resolution ?
Current-v oltage oscillogram
1 mm
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 5
Methods overview
Current pulse measurements (Current probes/Rogowski coils)
+ Mandatory information, but often difficult to measure
- No spatial information
Optical and spectroscopic methods
+ Passive methods, easy to apply, “intuitive”
+ Independent from gas and discharge type
- Limited to emission indirect information
Laser diagnostics (LIF, TALIF Volker Schulz-von der Gathen)
+ Direct information on density, field, …
- Specified diagnostic systems etc.
Mass spectrometry (Achim von Keudell, Jan Benedikt,)
+ Direct and un-specified excess
- Gas sampling limited to stable compounds
Surface charge measurements
Quantitative measurement of deposited charges
Simulation (Fluid, hybrid, …)
Needs experimental verification
Microdischarge investigation: Single filaments
Volume Barrier Discharge (VBD)
asymmetric symmetric
Negative Corona Discharge (-CD)
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 6
Fast current measurements
duration: 1-10 ns
transported charge: 100-1000 pC
current density: 100-1000 A cm-2
ICCD-camera (short exposure time photos)
Principle Image intensification by micro-channel plate; CCD-Sensor
Parameters ∆t down to 2 ns (new: down to 80 ps, Lav ision f ast gated iCCD)
Gain 105 … 106
Pecularities Temporally resolved measurement only if pulsed driven
Photos of individual MDs or discharge channels
Hamamatsu
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 7
ICCD-camera (short exposure time photos)
Volume Barrier Discharge (VBD) Positive Corona
T.M.P. Briels et al. J. Phys. D: Appl. Phys. (2008)
R. Brandenburg et al. J. Phys. D: Applied Phys. (2005)
Stereoscopic ICCD-imaging (pos. corona)
Discharge channels
analyzed in full 3D
Reconnection and merging of discharge channels
Branching angles
E.M. van Veldhuizen et al. Eur. Phys. J. - Appl. Phys. 47, 22811 (5p) (2009)
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 8
Plasma bulltes (Plasma jet)
E. Kindel, H. Lange et al.; GD 2008 Cardiff
Striated MD in asymmetric volume BD in Ar
Appearence of striated channel
dependent on argon gas purity
(argon flow rates above 100 sccm)
and applied voltage amplitude
Moste stable striated regime at
2 kVp-p (f= 60 kHz; T= 16 µs)
striated
non-striated
T. Hoder et al. Phys. Rev. E 2011
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 9
Reconstruction of temporal development
Simultaneous recording of current and ICCD-photo (gate-signal)
“Sorting” of ICCD-photos according to relation between ICCD-gate and
current pulse
Spatio-temporally resolved development
time
1. glow-discharge-like
structure 2. striated column and
extended cathode layer 3. striated structure decay
tow ards cathode
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 10
MD striation mechanism
Scaling parameters from scaling law theory for low pressure discharges:
i = 0.8 mA, r = 60 µm, λ = 200 to 300 µm
i/r ≈ 13 A/cm, p·r = 5 Torr·cm, 3 ≤ λ/r ≤ 5
Similar to striations in low pressure glow discharges
Different diameter of the cathode layer - channel constriction
different current densities at the cathode layer and in the channel
electron density gradient local disturbance & spatial electron relaxation
Energy dissipation length λe(U) = 196 µm (theory*) corresponds
to distance between the neighboring striations λ
*D. Loffhagen, M. Becker; INP Greifswald
0.12 mm 0.7 mm
λ
Streak camera (optoscope)
Principle Temporal profile transformed into spatial profile by defined
deflection in streak tube and (I)CCD
Parameters ∆t down to 1 ps
Gain 105 … 106
Pecularities Temporally resolved investigation of individual MDs
One spatial dimension
I(t)
I(x)
Hamamatsu
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 11
Streak photos of positive coronas
O. Eichwal d et al.; J. Phys. D: Appl. Phys. 41 ( 2008) 234002
Primary streamer (ps)
and secondary streamer
(ss)
Return stroke (return
streamers) and spark
(S) formation
~ 50 ns
Marode 1974 Sigmond 1983 Eichwald 2008
7mm
R.S. Sigmond; J. Appl. Phys. 56 (5),1 (1984)
E. Marode; Journal of Applied Physics, Vol. 46, No.5 (1975); Raizer “Gas discharge physics” (Springer)
Streak photos in volume BD
R.-J. Zahn S. M üller, 8th Int. Symposium on Science & Technolog yof Light Sources, Greifswald (1998).
Kr/He/Cl2 @ 400 mbarAir
C. Heuser, Diss. R WTH Aachen; G. J. Pietsch, Contributi ons to Plasma Physics 41, 620-628 (2001);
Optical streak Electro-Optical streak
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 12
2929
Pulsed driven volume BD in N2/O2
1mm
Dielectric: Al2O3(εr ≈ 9),
about 0.5 mm thick
„Square wave“HV-pulses:
UP= 7 … 10 kV;
dU/dt ~ 250 V/ns;
f = 10 kHz
Simultaneous measurement
with ICCD and streak camera
Electrical diagnostics
Discharge cell Diagnostics
30
50 75 100 125 150 175 200
0
25
50
75
Rising slope
Falling slope
Discharge currentdevelopment
t / ns
IDBD
/mA
30
Electrical measurements
One MD in the rising and in the
falling slope of pulsed high
voltage
Similar current pulses at both slopes
Decreases current pulse amplitude
and duration with increasing [O2]
0.1 vol.% O2 in N2:
Q= 1 nC
Eel ≈ 10 µJ
Pel ≈ 100 mW
Voltage
Current
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 13
3131
Streak-Camera imaging: single MD
32
Streak-camera imaging: 1,000 MDs acc.
Cathode directed
ionisation front / streamer
Glow region after
streamer passage
Polarity-Difference:
Longer MD duration in
case of falling slope
Larger dark space in
case of rising slope
1mm
A
C
1mm
C
A
RisingslopeFallingSlope
20 ns5 ns
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 14
3333
Cathode directed streamers
1mm
A
C
1mm
vRS
≈ 1.3 106 m/s
C
A
vFS ≈ 0.6 106
m/s
5 ns
vRS ≈
1.1 106 m/s
vFS ≈
1.1 106 m/s
5 ns
Duty cycle 10% (tPulse = 10 µs) Duty cycle 50% (tPulse = 50 µs)
Short duty cycle
(tpulse= 10 µs,
tpause= 90 µs)
vRS ≈ 2 vFS
Symmetric pulse
(tPulse = tPause= 50µs):
vRS ≈ vFS
Streamer velocity and
MD-structure depend
on time between MDs
RisingslopeFallingSlope
H. Höft, M. Kettlitz, T. Hoder et al., submitted to J Phys D
Cathode directed streamers (short duty cycle)
T. Hoder, H. Höft, M. Kettlitz et al., submitted to Physics of Plasmas
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 15
Cross-Correlation Spectroscopy (CCS)
Principle Time-correlated single photon counting (TC-SPC)
with reference signal from MDs itself
Parameters ∆t down to 12 ps
Gain up to 108
∆λ about 0.03 nm
Pecularities highest sensitivity
temporally and spectrally resolved investigation of repetitive,
but erratic appearing discharge events
averaging over many MDs (stability required)
2D spatial resolution possible
TC-SPC Board
High Gain
Photomultiplier (PMT)
CCS principle
SYNC-Signal:
• represents shape of
the f ull light pulse
• utilisation !!!
START STOP
Delay
Single Photon
Accumlation
MAIN-Signal:
• random single photons
• spatially resolv ed
• spectrally resolv ed
Microdischarge
First counted photon
time
Time inf ormation
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 16
High-Gain Photomultiplier
W. Becker, Becker-Hickl GmbH Berlin
Gain of up to 108
CCS set-up
SYNCMAIN
Imaging
Optics
Mono-
chro-
mator
PMT
(low Gain)
PMT
(high Gain)
TAC
ADC
Delay cable
CFDCFD
‘Start‘ ‘Stop‘
Microdischarge
Memory-address no count, if
no correlation
MEM
TC-SPC Module
Routing
device
HV-PS
HV
TTL
(Trigger)
MEM-segment
control
SYNCMAIN
Imaging
Optics
Mono-
chro-
mator
PMT
(low Gain)
PMT
(high Gain)
TAC
ADC
Delay cable
CFDCFD
‘Start‘ ‘Stop‘
Microdischarge
Memory-address no count, if
no correlation
MEM
TC-SPC Module
Routing
device
HV-PS
HV
TTL
(Trigger)
MEM-segment
control
HV-PS – High voltage power suppl y
PMT – Photomultiplier
CFD – Constant fraction discriminator
TAC – Time-to-amplitude convertor
ADC – Analog-digital converto r
ME M - Memory
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 17
1. negative Sys. FNS
2. positive Sys. SPS
N2
12
10
8
6
4
2
0
0.8 1.8 2.4
U, eV
R,Å
')( 3
2 υuCN Π
υ)( 1
2 gXN Σ
Emission spectrum in air
eV19Enm391h)X(N)B(N 0,B0''g
2
20'u
2
2 ==λν+Σ→Σ =υ
++
=υ
++
eV11Enm337h)B(N)C(N 0,C0''g
3
20'u
3
2 ==λν+Π→Π =υ=υ
47
Microdischarge development (VBD)
1. Pre-breakdown phase:
several 100 ns,
localised (residual surface charges)
3. Relaxation (decay) phase:
compensation of external E-field
outward directed propagation of
surface discharges
2. Breakdown phase:
cathode directed
ionization front (2ns),
0
CATHODE (-)
ANODE (+)
x(mm)
r (mm)
0
0.2
0.4
0.6
0.8
1.0
0.2-0.2
anode glow and surface discharge
R. Brandenburg et al. J. Phys . D: A pplied P hys. (2005)
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 18
Microdischarge development (VBD in air)
R. Brandenburg et al, IEEE Trans. Plasma Sci. (2008)
SPS:11eVne∘∘∘∘E/n
FNS:19eVhighE/n
Development along MD-axis in the volume
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 19
Asymmetric volume barrier discharges
T. Hoder et al. J.Phys. D: Appl. Phys. 43 ( 2010) 124009
+
-
M+D-
SPS
FNS
Pre-breakdown (Townsend) phase
Pre-breakdown phase of several 100 ns
Raether-Criterion not fullfilled
18<∫ dxeffα
( )cmTorrpd ⋅≈ 100
Townsend-breakdown, localised due to minor field inhomogenity by
residual surface charges (valid for repetitive mode)
Accumulation of positiv ions during Townsend phase streamer start
Yu. Yurgelenas et al.; Plasma Phys. and Controlled Fusion (2005)
SPS
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 20
Pre-breakdown (Townsend) Phase
Dielectric cathode (M+D-): Emission of residual surface electrons
Shorter Townsend-prephase and stepest luminosity increase
Dielectric anode (M-D+): Positive residual surface charge
Local field increase and this enhanced pre-phase
Intensity (photons)
measured closed to
anode
T. Hoder et al. J.Phys. D: Appl. Phys. 43 ( 2010) 124009
Cathode directed ionisation front
Cathode directed propagation of increasing field maximum
(positive streamer)
Velocity depends on distance from cathode (v = 105 … 2 106 m/s),
No v- dependence on (N2-O2) gas composition in symmetric VBD
Velocity dependent on discharge configuration (sym. vs asym. VBD)
K.V. Kozlov et al..; J. Phys. D: Appl. Phys. (2005)
FNS
Position(mm)
time (ns)∆t
∆z
Anode
Cathode
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 21
Ionization front (pos. streamer)
Dielectric cathode (M+D-): Emission of residual surface electrons
More effective γ-processes Pos. charging of D slower streamer
Dielectric anode (M-D+): More effective α-processes (bulk)
No reversed field by surface charge deposition and secondary electron
emission Faster streamer
T. Hoder et al. J.Phys. D: Appl. Phys. 43 ( 2010) 124009
CB
eff
CB
eNCB
CB
n
nn
n
E
k
dt
dn
,
,
,
,
2
τ
−⋅⋅





=
C
effCC
B
effBB
C
B
C
B
II
II
A
A
C
n
E
k
k
τ
τ
/
/
00
00
+
+
⋅





⋅=





•
•
Theory
Experiment
• local field approximation
• „strong“ and monotonous function
( EC,0= 11 eV << EB,0 =19 eV )
),(),( ,, tzntzI CBCB ∝
E/n
(z,t)
ne (z,t)
ne
max
particle balance equ.
Evaluation of plasma parameters (model)
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 22
Evaluation of plasma parameters (model)
0,0001
0,001
0,01
0,1
1
100 1000 10000
E/n
10
21
, Vm
2
R(391/337)
Steady
Trendline
Pulsed
Kim et al. [6]
Crey ghton [2]
Dy akov et al. [4]
P. Paris; J Phys D (2005); Uni versity of Tartu
Model independent calibration in progress
HG
lamp
Mono-
cromator
PM
RHV power –
supply +
Gas inlet
Vacuum
gauge and
pump
Ammeter
Filter
Counter
PC
Metal
Insulator
Quartz
Anode
Based on Townsend discharge (cell from Universtity of Tartu)
Cathode
Anode
Air
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 23
Plasma parameters
K.V. Kozlov et al : J. Phys. D: Appl. Phys. 2001
cathode
(glass)
cathode
(glass)
(glass)
anode
(glass)
anode
Td
1Td = 10-17 V cm2
electronic dissociation
O2 + e → O + O + e
PENNING dissociation
N2 + e → N2
∗ + e
N2
∗ + Ο2 → Ν2 + O + O
kd
kd (E/n (z,t)) • ne(z,t) • nO2
experiment
ke
E/n high ne high
Two regions
of high chemical
activity
within MD
E/n; ne O-Atom generation
ke (E/n (z,t)) • ne(z,t) • nN2
Calculation based on experimental results
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 24
0,0 0,2 0,4 0,6 0,8 1,0
0,0
0,2
0,4
0,6
0,8
1,0
ANO DECATHODE
Ref. [17 ]
This work
[O3
]/[O3
]max
x/d
Absorption measurements
C. HEUSER (1985)
pulsed mode
Calculated based
on CCS-results
(repetitive mode)
Calculated O3 Concentration Profiles
raw assumption: complete O to O3 conversion
E/n - 2D, symmetric BD
K. V. Kozl ovand H.-E. Wagner,
Contrib. Plasma Phys. (2007)
1Td = 10-17 V cm2
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 25
Time constants
K.V. Kozlov et al : J. Phys. D: Appl. Phys. 2005
2222 O
C
ON
C
NC
rad
C
eff
nKnK
11
++
τ
=
τ
a) Pancheshnyi et al., Chem.
Phys. 262 (2000) 349;
b) b) Mitchell, J. Chem. Phys. 53,
5 (1970) 1795
C
O
C
N 22
KK <<
In regions of relaxating plasma:
decay process for estimation of effective lifetimes
Quenching!
SBD configuration for MD studies
Localization & stabilization for time-consuming CCS measurements
- Tw o needle electrodes (Ø 0,4 mm, chrome- nickel- steel- alloy)
- Elektrode gap d= 1.15 mm
Dielectric material: Al2O3 , 0.6 mm thickness
Gas: dry air
dielectric
4 … 13 kVpp
~ 60 kHz
Exposed needle electrode
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 26
Discharge generation
T. Hoder, H. Grosch et al., EPJD 2010; IEEE Trans. Plas. Sci. 2011
Field configuration: Calculated stream lines and potential
Surface dischargeVolume discharge and
surface discharge
Surface Barrier Discharges (SBD)
Applied Voltage closed to burning voltage one MD per half period (HP)
cathode anode
(exposed) (cov ered)
Exposure time: 8,5 µs
Negative half period
f aint discharge activity
at the tip of cathode
anode cathode
(exposed) (cov ered)
Exposure time: 8,5 µs
Positive half period
Amplitude range: 2 mA - 40 mA
Av erage amplitude: ~ 12 mA
Av erage rise time: ~ 2 ns
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 27
CCS results
Positive HP: exposed electrode= anode
Pre-breakdown phase
Cathode directed ionising front („streamer“)
with decrasing velocity (v= 3.0·105 m/s -1.5·105 m/s)
Comparison of different BDs
v max
106 m/s
v -slope increasing
106 m/s
105
m/s on dielectric
increasing
decreasing on dielectric
105 m/s
decreasing
T. Hoder et al.; J.Phys. D: Appl. Phys. 2010; H. Grosch et al., EPJD, 2010
Symmetric VBD Coplanar Discharge Surface Discharge
Dielectric (-)
Dielectric (+)
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 28
MD propagation on dielectric barrier
Niemeyer, L.; IEEE Trans. Dielectr. Electr. Insul. (1995), Vol.2 No.4, 510- 528
Coplanar Discharge Surface Discharge
Dielectric (-)
Dielectric (+)
dielectric
cathode anode
dielectric
cathode
anode
External electric field:
decraeses along
MD path
Surface processes:
negative residual
charge (e-)
surface ionization αS
(detrapping, photo
effect, ion impact)
surface attachment ηS
Red: Streamlines
Blue: Equipotential lines
Trichel pulse corona (negative corona)
SPS (337 nm, 11 eV)
FNS (391 nm, 19 eV)
1. Electron multiplication
phase (120 µm)
2. pos. streamer
3. anode directed streamer
T. Hoder et al., prep. Appl. Phys. Lett.
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 29
Surface charge measurements
M. Bogaczyk, H.-E. Wagner, Uni. Greifswald
Summary
Fast optical and spectroscopic methods = powerfull tools for
discharge diagnostics
CCS as high sensitive method for spectroscopic investigation
Microdischarge development with high resolution (∆t,∆x,∆λ)
Estimation of plasma parameters (E/n; τeff, ne/ne,max)
Microdischarge development in barrier discharges:
(1) Townsend-prephase
(2) cathode directed ionization front (pos. streamer)
(3) decay phase
Quantified determination of positive and negative surface
charges by Pockels-effect
positive and negative surface charge density profiles
significantly different due to the electron mobility
positive and negative charges can exist simultaneously
memory-effect important for discharge re-ignition
R. Brandenburg (INP Greifswald)
Innolec Lectureship Brno 2012R.
Brandenburg, INP Greifswald
Part 2: Diagnostics 30
Outlook
Finished
E/n-calibration of CCS device for systematic determination of
plasma parameters (corona discharge)
Future work:
To correlate fast spectroscopic and optical investigation with
measurements of surface charges
structure and development (diffuse vs. filamentary)
role of surface processes (e.g. exoemission)
Study of the correlation between plasma physics and chemistry
“From the microdischarge to the plasmareactor”
86
Acknowledgement
University of Greifswald:
H.-E. Wagner, F. Miethke, J. Meichsner,
M. Bogaczyk, R. Wild, L. Stollenwerk
Lomonossov University Moscow:
K.V. Kozlov, A.M. Morozov
INP Greifwald:
T. Hoder, H. Grosch, R. Basner, W. Reich,
J. Schäfer, T. Gerling, R. Bussiahn, E. Kindel,
M. Kettlitz, H. Höft, K.-D. Weltmann
Masaryk University Brno:
M. Cernak, D. Trunec, Z. Navratil, P. Stahel,
J. Janca, J. Jansky
Support:
DFG: TR 24 “Fundamentals of complex plasmas”
BMBF: “ForMaT - InnoPlas”