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A note on longitudinal ampere forces in gaseous conductors
PHYSICS LETTERS
Volume 11 IA. number 6
A NOTE ON LONGITUDINAL
AMPERE FORCES IN GASEOUS
23 September 1985
CONDUCTORS
Jan NASILOWSKI Instytut Elektrotechniki, 04 -703 Warsaw, Poland Received 3 June 1985; accepted for publication 9 July 1985
It is argued that longitudinal Ampere forces should act not only in solid conductors, but also in gaseous conductors like welding, switching and furnace arcs, and magnetically confined fusion plasmas. This topic is in need of quantitive research.
Graneau [l-4] has reminded us of the forgotten electrodynamics of A.M. Ampere. In 1986 we will celebrate the 150th anniversary of the death of this famous French scientist. It seems the usefulness of his ideas has not been completely superseded by Maxwell’s field theory. Pappas [5] also presented experimental evidence of the type of electrodynamic forces which are capable of shattering a copper conductor into many pieces without complete melting [6] (see fig. 1). Accompanying mechanical vibrations were simultaneously observed. Recently Graneau observed longitudinal Ampere forces in liquid arcs [7]. It is still early for scientists and engineers to have recognized the significance of these discoveries. Longitudinal forces should equally
exist in weak gaseous conductors. Examples are the welding arc, the switching arc, arcs used in metal furnaces, and the magnetically confined fusion plasma
PI. The longitudinal tension-like forces should tend to disrupt arc columns mechanically. When this occurs the driving voltage and the energy stored in the circuit will try and restore the current. This process should be repetitive and generate current fluctuations in what would normally be expected to be a steady arc burning process. Bergmann [9] writes that heavy-current arcs are accompanied by continuous acoustic phenomena, that is mechanical vibrations in the arc plasma. In a book by Granovsky [ 101 we find arc voltage oscillograms produced across a gas discharge gap of an
Fig. 1. 1 mm diameter Cu wire disrupted by dc single pulse into pieces. The specimens which stuck falling on the steel sheet, compared with 1 mm grid.
0.375-9601/85/$ 03.30 0 Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)
315
Volume 111 A, number 6
PHYSICS LETTERS
aperiodic circuit energized with dc voltage. The natural “spontaneous” oscillations of the voltage across the discharge gap fall either in the MHz or GHz band. The phenomenon was observed with both highcurrent mercury arcs and low-current glow discharges [ 111. In considering his experiments Granovsky writes: “The oscillations are generated by causes that reside in the gaseous gap of the circuit” and “It has been found that these oscillations are generated in the anode zone. There is the source of the energy which produces the instabilities”. Of course Granovsky knew nothing about Ampere longitudinal forces in 195 1, but his experiments confirm the existence of Ampere tension in gaseous conductors. The most important questions to be cleared up by further research are: 1. Does Ampere tension depend on the length of the gaseous current path? 2. To which ions does the Ampere tension attach itself? 3. Is the force constant or vibrational?
316
23 September 1985
If we combine the observations by Granovsky with my own discovery of the fragmentation of 1 mm diameter copper wires, as shown in fig. 1, we should suspect the forces to be vibrational of nature [6]. References [ 11 P. Graneau, Phys. Lett. 97A (1983) 253. [2] P. Graneau, Nuovo Cimento 78B (1983) 213. [3] [4] [S] [ 61
[ 71 [8] [ 91
[ 101 [ 1 l]
P. Graneau, J. Appl. Phys. 155 (1984) 2598. P. Graneau, IEEE Trans. Magnet. 20 (1984) 444. P.T. Pappas, Nuovo Cimento 76B (1984) 189. J. Nasilowski, Exploding wires, Vol. 3 (Plenum, New York, 1964). P. Graneau and P.N. Graneau, Appl. Phys. Lett. 46 (1985) 468. J. Nasilowski, IEEE Trans. Magnet. 20 (1984) 2158. L. Bergmann, Der Ultraschall und seine Anwendung (Zurich, 1956). V.L. Granovsky, Electric current in gases, Vol. 1 (Gos. Izdat. Tech. Teoret. Lit., Moscow, 1951) pp. 381,382, in Russian. V. Granovsky and L. Bykhovskaya, J. Phys. (Moscow) 10 (1946) 351.
Volume 11 IA. number 6
A NOTE ON LONGITUDINAL
AMPERE FORCES IN GASEOUS
23 September 1985
CONDUCTORS
Jan NASILOWSKI Instytut Elektrotechniki, 04 -703 Warsaw, Poland Received 3 June 1985; accepted for publication 9 July 1985
It is argued that longitudinal Ampere forces should act not only in solid conductors, but also in gaseous conductors like welding, switching and furnace arcs, and magnetically confined fusion plasmas. This topic is in need of quantitive research.
Graneau [l-4] has reminded us of the forgotten electrodynamics of A.M. Ampere. In 1986 we will celebrate the 150th anniversary of the death of this famous French scientist. It seems the usefulness of his ideas has not been completely superseded by Maxwell’s field theory. Pappas [5] also presented experimental evidence of the type of electrodynamic forces which are capable of shattering a copper conductor into many pieces without complete melting [6] (see fig. 1). Accompanying mechanical vibrations were simultaneously observed. Recently Graneau observed longitudinal Ampere forces in liquid arcs [7]. It is still early for scientists and engineers to have recognized the significance of these discoveries. Longitudinal forces should equally
exist in weak gaseous conductors. Examples are the welding arc, the switching arc, arcs used in metal furnaces, and the magnetically confined fusion plasma
PI. The longitudinal tension-like forces should tend to disrupt arc columns mechanically. When this occurs the driving voltage and the energy stored in the circuit will try and restore the current. This process should be repetitive and generate current fluctuations in what would normally be expected to be a steady arc burning process. Bergmann [9] writes that heavy-current arcs are accompanied by continuous acoustic phenomena, that is mechanical vibrations in the arc plasma. In a book by Granovsky [ 101 we find arc voltage oscillograms produced across a gas discharge gap of an
Fig. 1. 1 mm diameter Cu wire disrupted by dc single pulse into pieces. The specimens which stuck falling on the steel sheet, compared with 1 mm grid.
0.375-9601/85/$ 03.30 0 Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)
315
Volume 111 A, number 6
PHYSICS LETTERS
aperiodic circuit energized with dc voltage. The natural “spontaneous” oscillations of the voltage across the discharge gap fall either in the MHz or GHz band. The phenomenon was observed with both highcurrent mercury arcs and low-current glow discharges [ 111. In considering his experiments Granovsky writes: “The oscillations are generated by causes that reside in the gaseous gap of the circuit” and “It has been found that these oscillations are generated in the anode zone. There is the source of the energy which produces the instabilities”. Of course Granovsky knew nothing about Ampere longitudinal forces in 195 1, but his experiments confirm the existence of Ampere tension in gaseous conductors. The most important questions to be cleared up by further research are: 1. Does Ampere tension depend on the length of the gaseous current path? 2. To which ions does the Ampere tension attach itself? 3. Is the force constant or vibrational?
316
23 September 1985
If we combine the observations by Granovsky with my own discovery of the fragmentation of 1 mm diameter copper wires, as shown in fig. 1, we should suspect the forces to be vibrational of nature [6]. References [ 11 P. Graneau, Phys. Lett. 97A (1983) 253. [2] P. Graneau, Nuovo Cimento 78B (1983) 213. [3] [4] [S] [ 61
[ 71 [8] [ 91
[ 101 [ 1 l]
P. Graneau, J. Appl. Phys. 155 (1984) 2598. P. Graneau, IEEE Trans. Magnet. 20 (1984) 444. P.T. Pappas, Nuovo Cimento 76B (1984) 189. J. Nasilowski, Exploding wires, Vol. 3 (Plenum, New York, 1964). P. Graneau and P.N. Graneau, Appl. Phys. Lett. 46 (1985) 468. J. Nasilowski, IEEE Trans. Magnet. 20 (1984) 2158. L. Bergmann, Der Ultraschall und seine Anwendung (Zurich, 1956). V.L. Granovsky, Electric current in gases, Vol. 1 (Gos. Izdat. Tech. Teoret. Lit., Moscow, 1951) pp. 381,382, in Russian. V. Granovsky and L. Bykhovskaya, J. Phys. (Moscow) 10 (1946) 351.