A novel flux compression/dynamic transformer technique for high-voltage pulse generation

Novac, B.M.; Smith, I.R.; Goh, S.E.; Enache, M.C.; Gregory, K.; Senior, P.; Cliffe, R.J.; Burke, Robert A.; Stewardson, H.R.

doi:10.1109/ppc.1999.825481

Cited by 4 publications

(5 citation statements)

References 11 publications

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“…The experimental data obtained in the present work do not confirm the conclusion of [28,35,36] about the existence of the precursor. The velocity of the metallization wave D m determined from the time of magnetic compression is close to the expected shock-wave velocity D c , and the found value of α is close (with allowance for the analysis performed above) to the ratio u/D determined on the basis of the shock adiabat of the substance.…”

Section: Gilevcontrasting

confidence: 99%

“…The velocity of the metallization wave D m determined from the time of magnetic compression is close to the expected shock-wave velocity D c , and the found value of α is close (with allowance for the analysis performed above) to the ratio u/D determined on the basis of the shock adiabat of the substance. Thus, the two-stage mechanism of shockwave magnetic cumulation [28,35,36] does not find any evidence in experiments with an electromagnetic electrode gauge, in measurements of electrical conductivity, and in experiments on magnetic cumulation.…”

Section: Gilevmentioning

confidence: 88%

“…Another mechanism of shock-wave magnetic cumulation was proposed in [28,35,36]. According to this mechanism, noticeable electrical conductivity emerges in an elastic precursor propagating in the powder ahead of the main shock-wave front.…”

Section: Gilevmentioning

confidence: 99%

“…Let us compare the results of [28,35,36] with available data on shock compressibility of aluminum powders obtained by different experimental methods [30][31][32][33]37]. The elastic precursor was not registered for such materials, and shock-wave velocity was found to be a linear function of particle velocity.…”

Section: Gilevmentioning

confidence: 99%

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Experimental study of shock-wave magnetic cumulation

Гилев

2008

Combust Explos Shock Waves

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Experiments with aluminum, copper, and silicon powders are performed to study the mechanism of shock-wave magnetic cumulation. For all substances examined, the magnetic field as a function of the cavity area is described by a power dependence with a constant exponent α. The value of α depends substantially on the substance porosity and particle size. For copper and silicon powders and for small-size aluminum powder, the value of α is consistent with the ratio of the particle velocity u to the wave velocity D, as is predicted by a simple model of magnetic cumulation. For the fine and coarse aluminum powders, the value of α is noticeably smaller than the ratio u/D. The lower effectiveness of magnetic compression can be attributed to insufficiently high electrical conductivity (fine powder) and the emergence of conductivity with incomplete compression of the substance (coarse powder). In the first case, diffusion losses of the magnetic flux in the compressed substance are fairly noticeable. In the second case, the work against the magnetic forces is performed by a layer in the shocktransition region, which has a lower particle velocity. The mechanism of magnetic cumulation involves substance metallization under shock compression and expelling of some portion of the magnetic flux to the non-conducting region ahead of the shock front. The two-stage mechanism of cumulation known in the literature (metallization in the elastic precursor and subsequent compression of the field in the main wave) is not validated by experiments with measurements of the particle and wave velocities and electrical conductivity and by experiments on magnetic cumulation.

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Section: Gilevcontrasting

confidence: 99%

Section: Gilevmentioning

confidence: 88%

Section: Gilevmentioning

confidence: 99%

Section: Gilevmentioning

confidence: 99%

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Experimental study of shock-wave magnetic cumulation

Гилев

2008

Combust Explos Shock Waves

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“…More recently, the same basic approach was adopted at Loughborough in two important applications of an ongoing research program, but with the shock wave being produced by means of exploding foils. In the first application it was used in the production of high voltage pulses [3] and in the second simultaneously to stabilize electromagnetically driven coil implosions and to provide improved protection for sensors [4]. Uniquely, this enabled both the up and down sweeps of the magnetic pulse to be recorded [5].…”

Section: Introductionmentioning

confidence: 99%

Magnetic flux-compression driven by exploding single-turn coils

Novac

Hook

Smith

2010

2010 IEEE International Power Modulator and High Voltage Conference

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A novel hybrid approach to producing ultrahigh magnetic fields has been successfully demonstrated using a 20 kJ capacitor bank. The explosion of a single-turn copper coil at peak field is used to generate shock-waves, which in turn produce in the aluminum powder filling the single-turn coil a circular insulatormetallic transition advancing towards the coil centre and performing magnetic flux-compression. The flux compression almost precisely doubles the initial flux density generated by the coil, so that some of the Joule energy deposited in the coil is re-use during the process as kinetic energy, rather than being lost as in a standard single-turn experiment. Attempts to scale up the basic arrangement to 80 kJ were only partially successful, but it was nevertheless possible to significantly prolong the duration of the megagauss field that was produced. It is believed that a hybrid method using small explosive charges to produce the shock-waves necessary for flux-compression can certainly be used when attempting to produce record magnetic flux densities in indoor experiments, without the need for a large and costly MJ size capacitor bank.

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