Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 5

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

Search:
in the keywords:  47.65.-d
help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Mechanism of Wire Explosion Plasma Acceleration in Strong Axial Magnetic Field

100%
Adamian Y., Shneerson G.
Acta Physica Polonica A
|
2009
|
vol. 115
|
issue 6
1069-1071
EN
In previous wire explosion experiments significant rise of plasma expansion speed is registered when strong axial magnetic field (50 T) is applied. Sharp drop of media conductivity takes place in peripheral area because of density decrease. It is shown in this work that the conductivity drop is the main cause of plasma acceleration. During plasma expansion in axial field azimuthal current is induced. In plasma layer losing conductivity takes place azimuthal current energy release. As a result, pressure shock is formed and low-density external plasma layer is accelerated.
2
Content available remote

Influence of Electric Field on AC Magnetic Susceptibility of a Mineral Oil Based Ferrofluid

51%
Rajňák M., Dolník B., Tobiáš T., Paulovičová K., Kurimský J., Cimbala R., Kopčanský P., Timko M.
Acta Physica Polonica A
|
2018
|
vol. 133
|
issue 3
567-579
EN
In a ferrofluid, the magnetic susceptibility at low magnetic fields is sensitive to the size and shape of magnetic nanoparticles and their concentration in a liquid carrier. In this paper we report on the AC magnetic susceptibility of a ferrofluid based on a mineral oil and iron oxide nanoparticles coated with oleic acid. As this type of ferrofluid is of increasing interest for electrical engineering applications, we investigate the effect of an external electric field and an electric current flowing through the ferrofluid on the AC magnetic susceptibility at ambient conditions. It is known that the action of the electric field on the oil based ferrofluids can result in the particle assembling. Then, the induced structural changes may affect the magnetic susceptibility of the bulk ferrofluid. In our experimental study we observed that the ferrofluid magnetic susceptibility decreases with increasing electric field. However, a heating effect with increasing electric field was observed too. Hence, it is concluded that besides the structural changes, the Joule heating has an obvious impact on the magnetic susceptibility of the ferrofluid in the external electric field.
3
Content available remote

Wall Confinement Technique by Magnetic Gradient Inversion. Accelerators Combining Induction Effect and Pulsed Ionization. Applications

44%
Petit J., Geffray J.
Acta Physica Polonica A
|
2009
|
vol. 115
|
issue 6
1162-1163
EN
We published the first description of a disk-shaped MHD aerodyne, combining pulsed ionization and induction systems. Magnetic pressure tends to push away electric discharge, in region of low magnetic field. In the seventies the efficiency of the wall confinement, due to the inversion of the magnetic pressure gradient was demonstrated. It is time now for ambitious MHD projects. We have planned experimental studies of MHD acceleration, combining pulsed ionization, wall confinement and induction system. We intend to study pulsed ionization systems based on wall micro discharges or microwaves action. We present the different features of the project.
4
Content available remote

Wall Confinement Technique by Magnetic Gradient Inversion

44%
Petit J., Dore J.
Acta Physica Polonica A
|
2012
|
vol. 121
|
issue 3
611-613
EN
When a plasma is subjected to a transversal magnetic field and its Hall parameter is non-negligible, it weakens the local electric conductivity value. If an electric discharge is created near a wall and the magnetic field decreases with distance, the electric discharge will follow a path that minimises the streamer's electric resistance, which could expel it far from the wall. One solution to ensure that it remains up against the wall is by inversion of the magnetic field's gradient by arranging that field B be minimal at the wall. In the experiment we are presenting, effected in a low-density gas, in order to obtain a high value for the Hall parameter using simple permanent magnets, we will show the remarkable efficiency of this parietal confinement method and present the main lines of the programme of which this experiment forms part and whose successful realization will be the demonstration of the feasibility of the displacement of disk-shaped MHD aerodynes at supersonic speed without creating either shock waves or turbulence, an approach that we have already set out in numerous publications.
5
Content available remote

MHD Flow-Control for Hypersonic Flight

38%
Petit J., Geffray J.
Acta Physica Polonica A
|
2009
|
vol. 115
|
issue 6
1149-1151
EN
At the beginning of the seventies, experimental research using short duration supersonic shock driven wind tunnel were conducted and showed the efficiency of Lorentz force action on supersonic (Mach 1.4) dense (1 bar) low magnetic Reynolds number hot (10 000 K) argon flows. When working as a generator, the linear Faraday MHD converter was efficient enough, due to high electrical conductivity (3000 S/m) to create a front shock wave at the intake of the constant cross-section MHD converter. Accelerations up to 5000 m/s were obtained in 10 cm long channels. This suggested the possibility to achieve complete shock wave and turbulent wake cancellation, through MHD bypass concept. Such work gave publications in peer-reviewed journals and presentation in international MHD meetings (French Academy of Sciences 1970, Moscow 1983, Tsukuba 1986, Beijing 1992). The work was conducted both through computational simulations (based on the method of characteristics) and hydraulic simulation experiments. We present the synthesis of such studies through a project of a hypersonic vehicle based on an MHD bypass concept, landing under its own steam, using classical turbojets. Then, at Mach 3 and high altitude, MHD controlled inlets are opened. A wall converter slows down the hypersonic incoming air flow, without excessive heating, feeding a ramjet system. The subsequent electric power provides an additional impulse to the flow in the exhaust section. Cruise Mach number: 12. Local Hall parameter regime produces high voltage that, sent to the leading edges, creates a plasma cushion which prevents too high thermal flux. Lift is provided by wave riding technique. Additional rocket propeller could transform it as a reusable space launcher.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.