| 1. |
- Alfvén, Hannes
(författare)
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Cosmology : Myth or science?
- 1992
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Ingår i: IEEE Transactions on Plasma Science. - : Institute of Electrical and Electronics Engineers (IEEE). - 0093-3813 .- 1939-9375. ; 20:6, s. 590-600
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Tidskriftsartikel (refereegranskat)abstract
- This paper examines critically the history of cosmology and presents ideas that lay the foundation of the plasma universe.
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| 2. |
- Alfvén, Hannes
(författare)
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Cosmology in the plasma universe - an introductory exposition
- 1990
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Ingår i: IEEE Transactions on Plasma Science. - : Institute of Electrical and Electronics Engineers (IEEE). - 0093-3813 .- 1939-9375. ; 18:1, s. 5-10
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Tidskriftsartikel (refereegranskat)abstract
- Acceptance of the plasma universe model is now leading to drastically new views of the structure of the universe. The basic aspects of cosmological importance are: (a) the same basic laws of plasma physics hold everywhere; (b) mapping of electric fields and currents is necessary to understand cosmic plasma; (c) space is filled with a network of currents leading to the cellular and filamentary structure of matter; and (d) double layers, critical velocity, and pinch effects are of decisive importance in how cosmic evolves. A review is presented of a number of the outstanding questions of cosmology in the plasma universe.
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| 3. |
- Alfvén, Hannes
(författare)
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Double-layers and circuits in astrophysics
- 1986
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Ingår i: IEEE Transactions on Plasma Science. - : Institute of Electrical and Electronics Engineers (IEEE). - 0093-3813 .- 1939-9375. ; 14:6, s. 779-793
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Tidskriftsartikel (refereegranskat)abstract
- As the rate of energy release in a double layer with voltage ΔV is P ≈ IΔV, a double layer must be treated as a part of a circuit which delivers the current I. As neither double layer nor circuit can be derived from magnetofluid models of a plasma, such models are useless for treating energy transfer by means of double layers. They must be replaced by particle models and circuit theory. A simple circuit is suggested which is applied to the energizing of auroral particles, to solar flares, and to intergalactic double radio sources. Application to the heliospheric current systems leads to the prediction of two double layers on the sun's axis which may give radiations detectable from Earth. Double layers in space should be classified as a new type of celestial object (one example is the double radio sources). It is tentatively suggested that X-ray and γ-ray bursts may be due to exploding double layers (although annihilation is an alternative energy source). A study of how a number of the most used textbooks in astrophysics treat important concepts such as double layers, critical velocity, pinch effects, and circuits is made. It is found that students using these textbooks remain essentially ignorant of even the existence of these concepts, despite the fact that some of them have been well known for half a century (e.g., double layers, Langmuir, 1929; pinch effect, Bennet, 1934).
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| 4. |
- Alfvén, Hannes
(författare)
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Model of the plasma universe
- 1986
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Ingår i: IEEE Transactions on Plasma Science. - : Institute of Electrical and Electronics Engineers (IEEE). - 0093-3813 .- 1939-9375. ; 14:6, s. 629-638
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Tidskriftsartikel (refereegranskat)abstract
- This paper is a review of a number of publications during the last ten years about those changes in our views of the cosmic environment that are the result of advances in plasma physics. To a large extent, these originate from new observational material that space research has supplied. An attempt is made to construct a model of the "plasma universe" which is claimed to be an alternative to the traditional " visual universe" based mainly on observations in the visual octave. Besides the Hubble expansion there is also a "knowledge expansion," which means that knowledge originating from plasma experiments in the laboratory is spreading to the magnetospheres and, it is predicted, sooner or later will also penetrate astrophysics in general. As an example of the usefulness of this model, it is applied to cosmogony, and a review is given of new results from an analysis of the Saturnian rings. The recent reconstruction of certain cosmogonic events with an accuracy better than 1 percent is reviewed and developed.
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| 5. |
- Appelgren, Patrik, et al.
(författare)
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Modeling of a small helical magnetic flux compression generator
- 2008
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Ingår i: IEEE Transactions on Plasma Science. - 0093-3813 .- 1939-9375. ; 36:5, s. 2662-2672
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Tidskriftsartikel (refereegranskat)abstract
- In order to gain experience in explosive pulsed power and to provide experimental data as the basis for computer modeling, a small high-explosive-driven helical magnetic flux-compression generator (FCG) was designed at the Swedish Defence Research Agency. The generator, of which three have been built, has an overall length of 300 mm and a diameter of 70 mm. It could serve as the energy source in a pulse-forming network to generate high-power pulses for various loads. This paper presents a simulation model of this helical FCG. The model, which was implemented in Matlab-Simulink, uses analytical expressions for the generator inductance. The model of resistive losses takes into account the heating of the conductors and the diffusion of the magnetic field into the conductors. The simulation results are compared with experimental data from two experiments with identical generators but with different seed currents, influencing the resistive losses. The model is used to analyze the performance of the generator.
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| 6. |
- Appelgren, Patrik, et al.
(författare)
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Small Helical Magnetic Flux-Compression Generators : Experiments and Analysis
- 2008
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Ingår i: IEEE Transactions on Plasma Science. - 0093-3813 .- 1939-9375. ; 36:5, s. 2673-2683
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Tidskriftsartikel (refereegranskat)abstract
- In order to gain experience in explosive pulsed power and to provide experimental data for modeling, a small high-explosive-driven helical magnetic flux-compression generator (FCG) was designed at the Swedish Defence Research Agency (FOI). The generator, of which three have been built, has an overall length of 300 mm and a diameter of 70 mm. It could serve as the energy source in a pulse-forming network to generate high power pulses for various loads. This paper presents the design of, and tests with, this helical FCG. The generator had an initial inductance of 23 mu H and was operated into a load of 0.2 mu H. The generator is charged with 0.27 kg of high explosives (PBXN-5). Various types of diagnostics were used to monitor the operation of the generator, including current probes, optical fibers, and piezo gauges. With seed currents of 5.7 and 11.2 kA, final currents of 269 and 436 kA were obtained, corresponding to current amplification factors of 47 and 39. The peak of the current was reached about 30 mu s after the time of crowbar. The two generators showed only small losses in terms of 2 pi-clocking. Using signals from optical fibers, the deflection angle of the armature could be determined to be 10 degrees in good agreement with hydrodynamic simulations of the detonation process and the detonation velocity to be 8.7 km/s in agreement with tabulated value.
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| 7. |
- Baránková, Hana, et al.
(författare)
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Conversion of Nitrogen and Carbon Oxides by the Atmospheric Hollow Cathode Discharges
- 2012
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Ingår i: IEEE Transactions on Plasma Science. - 0093-3813 .- 1939-9375. ; 40:5, s. 1324-1328
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Tidskriftsartikel (refereegranskat)abstract
- We have successfully tested the fused hollow cathode with aerodynamic stabilization as a 100% oxidation catalyst in conversion of NOx in air mixtures. Plasma chemical kinetics and the processing window width are controlled by plasma characteristics. Results show that, besides the plasma source design itself, the material of the electrodes plays a crucial role. It was found that, by using graphite electrodes, a 100% removal of NO from the air mixtures is possible without necessity of adding hydrocarbons. This paper presents results of oxygen screening, discusses the mechanisms of the process, and reports also on the CO2 reduction in some discharge regimes.
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| 8. |
- Blomberg, Lars G., et al.
(författare)
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The martian plasma environment : Electric field and Langmuir probe diagnostics
- 2003
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Ingår i: IEEE Transactions on Plasma Science. - : Institute of Electrical and Electronics Engineers (IEEE). - 0093-3813 .- 1939-9375. ; 31:6, s. 1232-1236
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Tidskriftsartikel (refereegranskat)abstract
- The plasma environment of Mars has been studied by a small handful of spacecraft. From the sparse observations that exist, one may conclude that the solar wind-Martian magnetosphere interaction is different in significant ways from the solar wind's interaction with Earth's magnetosphere. Mars offers an opportunity to make significant advances in our understanding of the fundamentals of the solar wind's interaction with cold celestial bodies, with suitable plasma instrumentation orbiting the planet. We briefly review what is known about Mars' plasma environment and address some scientific topics that can be studied by proper plasma instrumentation in Mars' vicinity, in particular the scientific potential of Langmuir probe measurements. Finally, we exemplify how the studies may contribute to an enhanced understanding not only of the plasma surrounding Mars, but also of the planet itself and its neutral atmosphere.
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| 9. |
- Bozhko, Igor, et al.
(författare)
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Corona discharge to water surface and its transition to a spark
- 2011
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Ingår i: IEEE Transactions on Plasma Science. - 0093-3813 .- 1939-9375. ; 36:5, s. 1228-1233
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Tidskriftsartikel (refereegranskat)abstract
- Impulse corona discharge in atmospheric air to the surface of a water layer with different electric conductivities isstudied. The discharge was initiated from a corona electrode consisting of a metallic disk with evenly distributed corona needles.The dependences of the magnitudes of the measured impulse currents on the polarity of the corona electrode as well as the parameters of the gas gap and liquid layer were obtained. An equivalent electric circuit of the discharge system was proposed,allowing for explanations of the regularities in the measured currents and also the role of the water layer as a factor affecting the transition of the corona discharge to a spark.
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| 10. |
- Bozhko, Igor, et al.
(författare)
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Determination of Energy of a Pulsed Dielectric Barrier Discharge and Method for Increasing Its Efficiency
- 2017
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Ingår i: IEEE Transactions on Plasma Science. - 0093-3813 .- 1939-9375. ; 45:12, s. 3064-3069
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Tidskriftsartikel (refereegranskat)abstract
- A methodology for accurate determination of energy released in a unipolar impulse dielectric barrier discharge is proposed and verified utilizing experimental data. In theexperiments, the discharge was initiated in air under atmospheric pressure in a coaxial chamber with glass dielectric barrier located on the cathode by applying voltage pulses with the slew rate of ∼3e11 V/s. It is shown that the energy released in the discharge is defined by the charge accumulated on the dielectric barrier before application of a successive voltage pulse and the magnitude of the remaining barrier voltage is dependent on many factors, in particular, repetition frequency of the discharge pulses, conditions and material of the barrier, impedance of the external electrical circuit, etc. It is demonstrated that the effective discharging of the barrier can be achieved by introducing a magnetic switch, which is essentially a nonlinear inductance connected in parallel to the discharge gap. The use of the switch allows for increasing the discharge efficiency in ∼30% and provides a way for correct evaluations of its energy.
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