Plasma diagnostics by laser spectroscopic electric field measurement

Laser spectroscopic electric field measurements have the potential to become a versatile tool for the diagnostics of low-temperature plasmas. From the spatially and temporally resolved field distribution in the sheath close to electrodes or surfaces in general, a broad range of important plasma parameters can be inferred directly: electron temperature; ion density distribution; displacement-, ion-, electron-diffusion current density; and the sheath potential. Indirectly, the electron and ion energy distribution functions and information on the ion dynamics in the sheath can also be obtained. Finally, measurements in the quasi-neutral bulk can also reveal even the plasma density distribution with high spatial and temporal resolution. The basic concepts for analysis of the field data are introduced and demonstrated by examples in hydrogen discharges.

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Cometary ion dynamics observed in the close vicinity of comet 67P/Churyumov–Gerasimenko during the intermediate activity period

Astronomy and Astrophysics ◽

10.1051/0004-6361/201732082 ◽

2018 ◽

Vol 613 ◽

pp. A57 ◽

Cited By ~ 13

Author(s):

L. Berčič ◽

E. Behar ◽

H. Nilsson ◽

G. Nicolaou ◽

G. Stenberg Wieser ◽

...

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Electric Field ◽

Field Measurements ◽

Distribution Functions ◽

Activity Period ◽

Ion Density ◽

Ion Flow ◽

Velocity Distribution Functions ◽

Comet 67P

Aims. Cometary ions are constantly produced in the coma, and once produced they are accelerated and eventually escape the coma. We describe and interpret the dynamics of the cometary ion flow, of an intermediate active comet, very close to the nucleus and in the terminator plane. Methods. We analysed in situ ion and magnetic field measurements, and characterise the velocity distribution functions (mostly using plasma moments). We propose a statistical approach over a period of one month. Results. On average, two populations were observed, separated in phase space. The motion of the first is governed by its interaction with the solar wind farther upstream, while the second one is accelerated in the inner coma and displays characteristics compatible with an ambipolar electric field. Both populations display a consistent anti-sunward velocity component. Conclusions. Cometary ions born in different regions of the coma are seen close to the nucleus of comet 67P/Churyumov–Gerasimenko with distinct motions governed in one case by the solar wind electric field and in the other case by the position relative to the nucleus. A consistent anti-sunward component is observed for all cometary ions. An asymmetry is found in the average cometary ion density in a solar wind electric field reference frame, with higher density in the negative (south) electric field hemisphere. There is no corresponding signature in the average magnetic field strength.

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Plasma parameters and electron energy distribution functions in a magnetically focused plasma

Physics of Plasmas ◽

10.1063/1.4794841 ◽

2013 ◽

Vol 20 (3) ◽

pp. 034502 ◽

Cited By ~ 11

Author(s):

C. M. Samuell ◽

B. D. Blackwell ◽

J. Howard ◽

C. S. Corr

Keyword(s):

Energy Distribution ◽

Electron Energy ◽

Distribution Functions ◽

Electron Energy Distribution ◽

Plasma Parameters ◽

Energy Distribution Functions

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Dust, Field and Plasma instrument onboard ESA’s Comet Interceptor mission

10.5194/epsc2021-399 ◽

2021 ◽

Author(s):

Hanna Rothkaehl ◽

Nicolas Andre ◽

Uli Auster ◽

vincenzo Della Corte ◽

Niklas Edberg ◽

...

Keyword(s):

Particle Interaction ◽

Field Measurements ◽

Distribution Functions ◽

Space Environment ◽

Dust Particles ◽

Spatial Density ◽

Fluxgate Magnetometer ◽

Plasma Parameters ◽

Cometary Plasma ◽

Cometary Dust

The main goal of ESA&#8217;s F-1 class Comet Interceptor mission is to characterise, for the first time, a long period comet; preferably a dynamically-new or an interstellar object. The main spacecraft, will have its trajectory outside of the inner coma, whereas two sub-spacecrafts will be targeted inside the inner coma, closer to the nucleus. The flyby of such a comet &#160;will offer unique multipoint measurement opportunity to study the comet's dusty and ionised environment in ways exceeding that of the previous cometary missions, including Rosetta. &#160; The Dust Field and Plasma (DFP) instruments located on both the main spacecraft A and on the sub-spacecraft B2, is a combined experiment dedicated to the in situ, multi-point study of the multi-phased ionized and dusty environment in the coma of the target and &#160;its interaction with the surrounding space environment and the Sun. &#160; The DFP instruments will be present in different configurations on the Comet Interceptor spacecraft A and B2. To enable the measurements on spacecraft A, the DFP is composed of 5 sensors; Fluxgate magnetometer DFP-FGM-A, Plasma instrument with nanodust and E-field measurements capabilities DFP-COMPLIMENT, Electron spectrometer DFP-LEES, Ion and energetic neutrals spectrometer DFP-SCIENA &#160;and Dust detector DFP-DISC. On board of spacecraft B2 the DFP is composed of 2 sensors: Fluxgate magnetometer DFP-FGM-B2 and Cometary dust detector DFP-DISC. &#160; The DFP instrument will measure magnetic field, the electric field, plasma parameters (density, temperature, speed), the distribution functions of electrons, ions and energetic neutrals, spacecraft potential, mass, number and spatial density of cometary dust particles and the dust impacts. &#160; &#160; The full set of DFP sensors will allow to model the comet plasma environment and its interaction with the solar wind. It will also allow to describe the complex physical processes including wave particle interaction in dusty cometary plasma. &#160;

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Fast semi-analytical method for precise prediction of ion energy distribution functions and sheath electric field in multi-frequency capacitively coupled plasmas

Applied Physics Express ◽

10.7567/apex.11.056201 ◽

2018 ◽

Vol 11 (5) ◽

pp. 056201

Author(s):

Wencong Chen ◽

Xi Zhang ◽

Dongfeng Diao

Keyword(s):

Electric Field ◽

Energy Distribution ◽

Analytical Method ◽

Distribution Functions ◽

Ion Energy ◽

Capacitively Coupled ◽

Ion Energy Distribution ◽

Precise Prediction ◽

Coupled Plasmas ◽

Energy Distribution Functions

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Plasma diagnostics for complex plasmas under microgravity and on ground

Journal of Plasma Physics ◽

10.1017/s0022377812000128 ◽

2012 ◽

Vol 78 (3) ◽

pp. 289-294 ◽

Cited By ~ 2

Author(s):

MIKHAIL Y. PUSTYLNIK ◽

MARKUS H. THOMA ◽

GREGOR E. MORFIŁL ◽

RAINER GRIMM ◽

CHRISTIAN HOCK

Keyword(s):

High Speed ◽

Space Station ◽

Diagnostic System ◽

Background Plasma ◽

Ion Temperature ◽

Plasma Parameters ◽

Ion Density ◽

Many Body Systems ◽

Low Temperature Plasmas ◽

Complex Plasmas

AbstractComplex plasmas are low-temperature plasmas containing micron-sized particles (microparticles) such as dust grains. These are present in astrophysical systems (comets, molecular clouds, et al.) and in technological applications (microchip production by plasma etching, deposition of solar cells, et al.). Complex plasmas are also of interest in basic science because these are often used as models for many other strongly coupled many-body systems in solid state, fluid, or plasma physics. Since gravity has a strong influence on the microparticle component, experiments under microgravity (parabolic flights, sounding rockets, International Space Station (ISS)) are performed. Interaction between microparticles depends on plasma parameters such as ion density or ion temperature. Also, the presence of microparticles may change the properties of background plasma. Therefore, the background plasma needs to be characterized to provide adequate interpretation of the microgravity experiments. For this purpose a dedicated high-speed diagnostic system has been set up.

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