Kari Niemi

Search results

• 2024

  Ozone production by an He+O2 radio-frequency atmospheric pressure plasma jet driven by tailored voltage waveforms

  Harris, B., Dedrick, J. P., Niemi, K. & Wagenaars, E., 31 Jul 2024, In: Plasma Sources Science and Technology. 33, 14 p., 075020.

  Research output: Contribution to journal › Article › peer-review

  Open Access

  File
• 2022

  Effects of humidity on the dynamics and electron recombination of a pin-to-pin discharge in He + H2O at atmospheric pressure

  Brisset, A., Harris, B., Dickenson, A., Niemi, K., Walsh, J. & Wagenaars, E., 14 Apr 2022, In: Plasma Sources Science and Technology. 31, 4, 12 p., 045008.

  Research output: Contribution to journal › Article › peer-review

  Open Access

  File
• 2021

  Chemical kinetics and density measurements of OH in an atmospheric pressure He + O₂ + H₂O radiofrequency plasma

  Brisset, A. H. M. B., Gibson, A. R., Schröter, S., Niemi, K., Booth, J.-P., Gans, T., O'Connell, D. & Wagenaars, E., 4 May 2021, In: Journal of Physics D: Applied Physics. 54, 28, 29 p., 285201.

  Research output: Contribution to journal › Article › peer-review

  Open Access

  File
• 2020

  Gas temperature measurements in a pulsed, low-pressure inductively coupled plasma in oxygen

  Meehan, D., Niemi, K. & Wagenaars, E., 1 May 2020, In: Japanese Journal of Applied Physics. 59, SH, 7 p., SHHB03.

  Research output: Contribution to journal › Article › peer-review

  Open Access

  File

• Influence of surface materials on the volume production of negative ions in a radio-frequency driven hydrogen plasma

  Ellis, J., Branson, J., Niemi, K., Wagenaars, E. & Gans, T., 11 Sept 2020, (E-pub ahead of print) In: Journal of Physics D: Applied Physics. 53, 48

  Research output: Contribution to journal › Article › peer-review

  Open Access

  File

• Reproducibility of `COST Reference Microplasma Jets'

  Riedel, F., Golda, J., Held, J., Davies, H., Van Der Woude, M., Niemi, K., Bredin, J., Gans, T., Schulz-von der Gathen, V. & O'Connell, D., 17 Sept 2020, In: Plasma Sources Science and Technology. 29, 9, p. 1-12 12 p., 095018.

  Research output: Contribution to journal › Article › peer-review

  Open Access

  File

• The formation of atomic oxygen and hydrogen in atmospheric pressure plasmas containing humidity: picosecond two-photon absorption laser induced fluorescence and numerical simulations

  Schröter, S., Bredin, J., Gibson, A. R., West, A., Dedrick, J. P., Wagenaars, E., Niemi, K., Gans, T. & O'Connell, D., 15 Oct 2020, In: Plasma Sources Science and Technology. 29, 10, 17 p., 105001.

  Research output: Contribution to journal › Article › peer-review

  Open Access

  File

• The spatial distribution of hydrogen and oxygen atoms in a cold atmospheric pressure plasma jet

  Klose, S. J., Ellis, J., Riedel, F., Schröter, S., Niemi, K., Semenov, I., Weltmann, K.-D., Gans, T., O'Connell, D. & van Helden, J.-P., 21 Dec 2020, In: Plasma Sources Science and Technology. 29, 12, 12 p., 125018.

  Research output: Contribution to journal › Article › peer-review

  Open Access

  File
• 2019

  Disrupting the spatio-temporal symmetry of the electron dynamics in atmospheric pressure plasmas by voltage waveform tailoring

  Gibson, A. R., Donkó, Z., Alelyani, L. A. A., Bischoff, L., Hübner, G., Bredin, J., Doyle, S. J., Korolov, I., Niemi, K., Mussenbrock, T., Hartmann, P., Dedrick, J. P., Schulze, J., Gans, T. & O'Connell, D., 7 Jan 2019, In: Plasma Sources Science and Technology. 28, 1, 7 p., 01LT01.

  Research output: Contribution to journal › Article › peer-review

  Open Access

  File
• 2018

  Chemical kinetics in an atmospheric pressure helium plasma containing humidity

  Schröter, S., Wijaikhum, A., Gibson, A. R., West, A., Davies, H. L., Minesi, N., Dedrick, J. P., Wagenaars, E., de Oliveira, N., Nahon, L., Kushner, M. J., Booth, J.-P., Niemi, K., Gans, T. & O'Connell, D., 26 Sept 2018, In: Physical Chemistry Chemical Physics. 20, 37, p. 24263-24286 24 p.

  Research output: Contribution to journal › Article › peer-review

  Open Access

  File
• 2017

  Absolute ozone densities in a radio-frequency driven atmospheric pressure plasma using two-beam UV-LED absorption spectroscopy and numerical simulations

  Wijaikhum, A., Schröder, D., Schröter, S., Gibson, A. R., Niemi, K., Friderich, J., Greb, A., Schulz-von der Gathen, V., O'Connell, D. & Gans, T., 17 Oct 2017, In: Plasma Sources Science & Technology, IoP Publishing. p. 1-27 27 p.

  Research output: Contribution to journal › Article › peer-review

  Open Access

  File

• Controlled production of atomic oxygen and nitrogen in a pulsed radio-frequency atmospheric-pressure plasma

  Dedrick, J. P., Schröter, S., Niemi, K., Wijaikhum, A., Wagenaars, E., de Oliveira, N., Nahon, L., Booth, J.-P., O'Connell, D. & Gans, T., 15 Nov 2017, In: Journal of Physics D: Applied Physics. 50, 45, p. 1-7 7 p., 455204.

  Research output: Contribution to journal › Article › peer-review

  Open Access

  File
• 2015

  Atomic oxygen and hydroxyl density measurements in an atmospheric pressure RF-plasma with water admixtures using UV and synchrotron VUV absorption spectroscopy

  Schröter, S., Foucher, M., Niemi, K., Dedrick, J. P., de Oliveira, N., Joyeux, D., Nahon, L., Wagenaars, E., Gans, T., Booth, J.-P. & O'Connell, D., 2015, Proc 22nd ISPC. 4 p.

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

  Open Access

  File

• Influence of surface conditions on plasma dynamics and electron heating in a radio-frequency driven capacitively coupled oxygen plasma

  Greb, A., Gibson, A. R., Niemi, K., O'Connell, D. & Gans, T., 26 Jun 2015, In: Plasma sources science & technology. 24, 4, 14 p., 044003.

  Research output: Contribution to journal › Article › peer-review
• 2014

  Afterglow chemistry of atmospheric-pressure helium–oxygen plasmas with humid air impurity

  Murakami, T., Niemi, K., Gans, T., O'Connell, D. & Graham, W. G., 1 Apr 2014, In: Plasma sources science & technology. 23, 2, 12 p., 025005.

  Research output: Contribution to journal › Article › peer-review

• Energy resolved actinometry for simultaneous measurement of atomic oxygen densities and local mean electron energies in radio-frequency driven plasmas

  Greb, A., Niemi, K., O'Connell, D. & Gans, T., 11 Dec 2014, In: Applied Physics Letters. 105, 4 p., 234105.

  Research output: Contribution to journal › Letter › peer-review

  Open Access

  File
• 2013

  Absolute atomic oxygen and nitrogen densities in radio-frequency driven atmospheric pressure cold plasmas: Synchrotron vacuum ultra-violet high-resolution Fourier-transform absorption measurements

  Niemi, K., O'Connell, D., de Oliveira, N., Joyeux, D., Nahon, L., Booth, J.-P. & Gans, T., 2013, In: Applied Physics Letters. 103, 3, 4 p., 034102.

  Research output: Contribution to journal › Article › peer-review

• Chemical kinetics and reactive species in atmospheric pressure helium–oxygen plasmas with humid-air impurities

  Murakami, T., Niemi, K., Gans, T., O'Connell, D. & Graham, W. G., Feb 2013, In: Plasma sources science & technology. 22, 1, p. 1-29 29 p., 015003.

  Research output: Contribution to journal › Article › peer-review

• Comparison of a global model to semi-kinetic fluid simulations for atmospheric pressure radio-frequency plasmas

  Niemi, K., Gans, T. & O'Connell, D., Jun 2013, In: Plasma sources science & technology. 22, 3, p. 1-5 5 p., 032001.

  Research output: Contribution to journal › Article › peer-review

• Direct optical measurements of reactive nitrogen species (RNS) in cold atmospheric-pressure plasma jets

  West, A. T., Niemi, K., O'Connell, D., Gans, T. & Wagenaars, E., Aug 2013, Proc 21st ISPC. p. 1-3 3 p. 106OR

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

• Improved fluid simulations of radio-frequency plasmas using energy dependent ion mobilities

  Greb, A., Niemi, K., O'Connell, D., Ennis, G. J., MacGearailt, N. & Gans, T., May 2013, In: Physics of Plasmas. 20, 5, p. 1-9 9 p., 053502.

  Research output: Contribution to journal › Article › peer-review

• Interacting kinetics of neutral and ionic species in an atmospheric-pressure helium–oxygen plasma with humid air impurities

  Murakami, T., Niemi, K., Gans, T., O'Connell, D. & Graham, W. G., Aug 2013, In: Plasma sources science & technology. 22, 4, p. 1-12 045010.

  Research output: Contribution to journal › Article › peer-review

• The influence of surface properties on the plasma dynamics in radio-frequency driven oxygen plasmas: Measurements and simulations

  Greb, A., Niemi, K., O'Connell, D. & Gans, T., 9 Dec 2013, In: Applied Physics Letters. 103, 24, 244101.

  Research output: Contribution to journal › Article › peer-review
• 2012

  Atomic nitrogen measurements in an atmospheric-pressure plasma jet

  Wagenaars, E., Gans, T., O'Connell, D. & Niemi, K., 2012, XXI Europhysics Conference on the Atomic and Molecular Physics of Ionized Gases. European Physical Society, Vol. ECA 36A.

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

• Cold atmospheric pressure plasma jets: Interaction with plasmid DNA and tailored electron heating using dual-frequency excitation

  Niemi, K., O'Neill, C., Cox, L. J., Waskoenig, J., Hyland, W. B., McMahon, S. J., Reuter, S., Currell, F. J., Graham, W. G., O'Connell, D. & Gans, T., 2012, 17th International Conference on Atomic Processes in Plasmas (ICAPiP). Aggarwal, K. & Shearer, F. (eds.). MELVILLE: American Institute of Physics, Vol. 1438. p. 23-28 (AIP Conference Proceedings; vol. 1438).

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

• Two-photon Absorption Laser-Induced Fluorescence measurements of atomic nitrogen in a radio-frequency atmospheric-pressure plasma jet

  Wagenaars, E., Gans, T., O'Connell, D. & Niemi, K., Aug 2012, In: Plasma sources science & technology. 21, 4, p. 1-4 4 p., 042002.

  Research output: Contribution to journal › Article › peer-review
• 2011

  Cold atmospheric pressure plasma jets as sources of singlet delta oxygen for biomedical applications

  Sousa, J. S., Niemi, K., Cox, L. J., Algwari, Q. T., Gans, T. & O'Connell, D., 15 Jun 2011, In: Journal of Applied Physics. 109, 12, 8 p., 123302.

  Research output: Contribution to journal › Article › peer-review

• Correlation Between the Electrical and Optical Properties of an Atmospheric Pressure Plasma During Siloxane Coating Deposition

  Twomey, B., Nindrayog, A., Niemi, K., Graham, W. G. & Dowling, D. P., Feb 2011, In: Plasma chemistry and plasma processing. 31, 1, p. 139-156 18 p.

  Research output: Contribution to journal › Article › peer-review

• Energetic electron avalanches and mode transitions in planar inductively coupled radio-frequency driven plasmas operated in oxygen

  Zaka-ul-Islam, M., Niemi, K., Gans, T. & O'Connell, D., 25 Jul 2011, In: Applied Physics Letters. 99, 4, p. 1-3 3 p., 041501.

  Research output: Contribution to journal › Article › peer-review

• The role of helium metastable states in radio-frequency driven helium-oxygen atmospheric pressure plasma jets: measurement and numerical simulation

  Niemi, K., Waskoenig, J., Sadeghi, N., Gans, T. & O'Connell, D., Oct 2011, In: Plasma sources science & technology. 20, 5, 10 p., 055005.

  Research output: Contribution to journal › Article › peer-review
• 2010

  Atomic oxygen formation in a radio-frequency driven micro-atmospheric pressure plasma jet

  Waskoenig, J., Niemi, K., Knake, N., Graham, L. M., Reuter, S., Schulz-von der Gathen, V. & Gans, T., Aug 2010, In: Plasma sources science & technology. 19, 4, 11 p., 045018.

  Research output: Contribution to journal › Article › peer-review

• Diagnostic-based modeling on a micro-scale atmospheric-pressure plasma jet

  Waskoenig, J., Niemi, K., Knake, N., Graham, L. M., Reuter, S., Schulz-von der Gathen, V. & Gans, T., Jun 2010, In: PURE AND APPLIED CHEMISTRY. 82, 6, p. 1209-1222 14 p.

  Research output: Contribution to journal › Article › peer-review

• Diagnostic based modelling of radio-frequency driven atmospheric pressure plasmas

  Niemi, K., Reuter, S., Graham, L. M., Waskoenig, J., Knake, N., Schulz-von der Gathen, V. & Gans, T., 31 Mar 2010, In: Journal of Physics D: Applied Physics. 43, 12, 6 p., 124006.

  Research output: Contribution to journal › Article › peer-review

• Electrical, Thermal and Optical Diagnostics of an Atmospheric Plasma Jet System

  Nwankire, C. E., Law, V. J., Nindrayog, A., Twomey, B., Niemi, K., Milosavljevic, V., Graham, W. G. & Dowling, D. P., Oct 2010, In: Plasma chemistry and plasma processing. 30, 5, p. 537-552 16 p.

  Research output: Contribution to journal › Article › peer-review
• 2009

  Diagnostic based modeling for determining absolute atomic oxygen densities in atmospheric pressure helium-oxygen plasmas

  Niemi, K., Reuter, S., Graham, L. M., Waskoenig, J. & Gans, T., 12 Oct 2009, In: Applied Physics Letters. 95, 15, p. 1-3 3 p., 151504.

  Research output: Contribution to journal › Article › peer-review

• DIAGNOSTIC BASED MODELING FOR DETERMINING ABSOLUTE ATOMIC OXYGEN DENSITIES IN RADIO-FREQUENCY ATMOSPHERIC PRESSURE HELIUM-OXYGEN PLASMAS

  Reuter, S., Niemi, K., Graham, L., Waskoenig, J. & Gans, T., 2009, 4TH INTERNATIONAL CONGRESS ON COLD ATMOSPHERIC PRESSURE PLASMAS: SOURCES AND APPLICATIONS, PROCEEDINGS. Leys, C. & Morent, R. (eds.). GHENT: Universiteit Gent, p. 111-112 2 p.

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

• Generation of atomic oxygen in the effluent of an atmospheric pressure plasma jet

  Reuter, S., Niemi, K., Schulz-von der Gathen, V. & Doebele, H. F., Feb 2009, In: Plasma sources science & technology. 18, 1, p. - 9 p., 015006.

  Research output: Contribution to journal › Article › peer-review

• Space and phase resolved optical emission in mode transitions of radio-frequency inductively coupled plasmas

  O'Connell, D., Niemi, K., Zaka-ul-Islam, M. & Gans, T., 2009, SECOND INTERNATIONAL WORKSHOP ON NON-EQUILIBRIUM PROCESSES IN PLASMAS AND ENVIRONMENTAL SCIENCE. Petrovic, Z., Malovic, G. & Maric, D. (eds.). BRISTOL: IOP Publishing, p. - 8 p. (Journal of Physics ).

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

• The dynamics of radio-frequency driven atmospheric pressure plasma jets

  Schaper, L., Reuter, S., Waskoenig, J., Niemi, K., Schulz-von der Gathen, V. & Gans, T., 2009, SECOND INTERNATIONAL WORKSHOP ON NON-EQUILIBRIUM PROCESSES IN PLASMAS AND ENVIRONMENTAL SCIENCE. Petrovic, Z., Malovic, G. & Maric, D. (eds.). BRISTOL: IOP Publishing, p. - 8 p.

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
• 2008

  Absolute atomic oxygen density distributions in the effluent of a microscale atmospheric pressure plasma jet

  Knake, N., Reuter, S., Niemi, K., Schulz-von der Gathen, V. & Winter, J., 7 Oct 2008, In: Journal of Physics D: Applied Physics. 41, 19, p. - 6 p., 194006.

  Research output: Contribution to journal › Article › peer-review

• Absolute atomic oxygen density profiles in the discharge core of a microscale atmospheric pressure plasma jet

  Knake, N., Niemi, K., Reuter, S., Schulz-von der Gathen, V. & Winter, J., 29 Sept 2008, In: Applied Physics Letters. 93, 13, p. - 3 p., 131503.

  Research output: Contribution to journal › Article › peer-review

• Helicon mode formation and radio frequency power deposition in a helicon-produced plasma

  Niemi, K. & Kraemer, M., Jul 2008, In: Physics of Plasmas. 15, 7, p. - 11 p., 073503.

  Research output: Contribution to journal › Article › peer-review

• Spatially resolved diagnostics on a microscale atmospheric pressure plasma jet

  Schulz-von der Gathen, V., Schaper, L., Knake, N., Reuter, S., Niemi, K., Gans, T. & Winter, J., 7 Oct 2008, In: Journal of Physics D: Applied Physics. 41, 19, p. - 6 p., 194004.

  Research output: Contribution to journal › Article › peer-review
• 2007

  Anomalous helicon wave absorption and parametric excitation of electrostatic fluctuations in a helicon-produced plasma

  Kraemer, M., Aliev, Y. M., Altukhov, A. B., Gurchenko, A. D., Gusakov, E. Z. & Niemi, K., May 2007, In: Plasma Physics and Controlled Fusion. 49, 5A, p. A167-A175 9 p.

  Research output: Contribution to journal › Article › peer-review

• Diagnostics on an atmospheric pressure plasma jet

  Niemi, K., Reuter, S., Schaper, L., Knake, N., Schulz-von der Gathen, V. & Gans, T., 2007, First International Workshop on Nonequilibrium Processes in Plasma Physics and Studies of Environment. Petrovic, Z., Malovic, G., Tasic, M. & Nikitovic, Z. (eds.). BRISTOL: IOP Publishing, p. U152-U160 9 p.

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

• Optical diagnostics of micro discharge jets

  Schulz-von der Gathen, V., Buck, V., Gans, T., Knake, N., Niemi, K., Reuter, S., Schaper, L. & Winter, J., 2007, In: Contributions to plasma physics. 47, 7, p. 510-519 10 p.

  Research output: Contribution to journal › Article › peer-review
• 2006

  Determination of the degree of dissociation in an inductively coupled hydrogen plasma using optical emission spectroscopy and laser diagnostics

  Abdel-Rahman, M., Schulz-von der Gathen, V., Gans, T., Niemi, K. & Doebele, H. F., Nov 2006, In: Plasma sources science & technology. 15, 4, p. 620-626 7 p.

  Research output: Contribution to journal › Article › peer-review
• 2005

  Absolute atomic oxygen density measurements by two-photon absorption laser-induced fluorescence spectroscopy in an RF-excited atmospheric pressure plasma jet

  Niemi, K., Schulz-von der Gathen, V. & Dobele, H. F., May 2005, In: Plasma sources science & technology. 14, 2, p. 375-386 12 p.

  Research output: Contribution to journal › Article › peer-review

• Laser-induced fluorescence measurements of absolute atomic densities: concepts and limitations

  Dobele, H. F., Mosbach, T., Niemi, K. & Schulz-von der Gathen, V., May 2005, In: Plasma sources science & technology. 14, 2, p. S31-S41 11 p.

  Research output: Contribution to journal › Article › peer-review
• 2003

  Is the flow tube reactor with NO2 titration a reliable absolute source for atomic hydrogen?

  Niemi, K., Mosbach, T. & Dobele, H. F., 10 Jan 2003, In: Chemical Physics Letters. 367, 5-6, p. 549-555 7 p.

  Research output: Contribution to journal › Article › peer-review