Pulsotron-2 ignition conditions verification

Javier López
Chris Costa
Judith Atkins
Jorge Juan López

ABSTRACT

In the present paper the Pressure Ignition Conditions verification will be described, these were performed in October 2013 by an external certification company which checked all operations that were carried out, using calibrated and standard instruments and conventional formulas only.

This unprecedented procedure that was performed on a test fusion machine can be used in a similar way on other machines in order to establish a standard benchmark for fusion.

Pulsotron-2 is a Z-pinch machine designed to obtain ignition conditions for D-T or D-D fuel but also paving the way to aneutronic ones as Boron11-Proton and Lithium-6-proton

 
EQUIPMENT USED

As the tests had to be verified, all instrumentation must be standard and calibrated , not only to obtain the results but also the uncertainty in the measurement.

As long as the tests had to be verified, all instrumentation must be standard and calibrated, not only to obtain the results but also the uncertain in the measurement

We used a standard 2 channels high speed digital oscilloscope
Micro ohmmeter
LCR to measure the capacity of the capacitor bank

PARAMETERS TO BE MEASURED

The current was measured:  The two standard systems are by measuring the voltage drop through a resistor or by measuring the voltage drop through capacitors.  Both systems have given the same results in our previous tests taking into account the parasite values, but we decided to use the voltage drop due to the fact that it is not needed to use any filtering that could introduce more errors.

ECUATIONS

The maximum magnetic field was obtained from following formula:
Image

Where “r” is the plasma radius.  According to the needle sensors used the plasma radius is really compressed from initial one but we took the initial measure which is a worse case.
 
As long as we always used the international Units System, r is in meters, l in amps, B in Teslas and μo =4e-7*π
In order to reduce error we measured maximum current during more than 100 nanoseconds time.

Then it is obtained the maximum pressure:
Image

The double product Pmax*t can also be obtained where t is the time reached during Pmax.

TEST RESULTS

The result data of target shot number 309 is 8.18e15 pascals:

Image

It was very similar to target shot number 310 that was 7.75e15 pascals:

Image

Here is the verification data obtained in Pulsotron – 2 tests numbers 309 and 310 compared with other existing or building fusion machines:

Image

OTHER FUSION MACHINES RESULT

Using available information on papers or articles written in Internet, the following data on the other machines was obtained:
 
Sandia Z: This machine is the best documented one, see reference [1]
Pag 4: pressure 5-100MBar: that is 1E+11 pascals in S.I.
Pag 13: time=7ns:

Image

Then PTmax=1E+13*7E-09=7E+04 Pascals x second

NIF see reference [2]: NIF Project Status – 2012

Time: 4.2ns:

Image

Pressure: See reference [3]:
http://en.wikipedia.org/wiki/National_Ignition_Facility  50 Mbar

50 Mbar =50 x 1E+11 = 50E+11Pascals
PTmax=50E+11 * 4.2ns = 21000 Pascals x second

ITER See reference [4]: The only one article found is not signed and has not name: http://www.psfc.mit.edu/library1/catalog/online_pubs/iap/iap2011/cowley.pdf
Accordingly first page, the confinement time is 400 seconds
Pmax is 7 bar, 700kPa as can be seen in page 7:
Image

Por tanto Presion = 7 x 1E+05 = 7E+05 Pa

PTmax=7E+05*400 = 2.8E+08 Pascales x segundo

Por tanto Presion = 7 x 1E+05 = 7E+05 Pa
PTmax=7E+05*400 = 2.8E+08 Pascales x segundo

IVY MIKE and W-80 warheads, see reference [5]:

Thermonuclear weapon

Image

The initial radiation pressure at IVY MIKE was 7.3E+12 and W80 was 140E+12 pascals

Accordingly reference [6] maximum time was 80 nanoseconds, accordingly 4.4.3.5 Ignition, then multiplying the given pressure results we obtain:

PTmax of IVY Mike    = 7.3E+12 * 80ns =5.84E+05 Pa * s

PTmax of W-80          = 1.4E+14 * 80ns =1.12E+07 Pa * s

The verification documents can be shown on request.

Image

REFERENCES

[1]  High Energy Density Physics: Z-pinches and Pulsed Power
Dr. Christopher Deeney, Sandia National Laboratories, 2011

[2] NIF Project Status – 2012

[3] http://en.wikipedia.org/wiki/National_Ignition_Facility  

[4] The only one article found is not signed and has not name: http://www.psfc.mit.edu/library1/catalog/online_pubs/iap/iap2011/cowley.pdf

[5] Thermonuclear weapon
http://en.wikipedia.org/wiki/Thermonuclear_weapon

[6]  The Nuclear Weapons Archive, Elements of Thermonuclear Weapon Design 2005 http://nuclearweaponarchive.org/Nwfaq/Nfaq4-4.html

[7] Pulsotron-2 verification

 

About jlopez2022

Experimental Physicist
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