2014-July Pulsotron-2 Plasma Thrusters test report

Javier Luis López Segura,
Jorge Juan López,
Judy Atkins
Pulsotrón SL


Abstract.-
Cuenca.  In the July 2014 test campaign different ion speed measurement sensors installed in the Pulsotron-2 test tower were tested.  Using said sensors plasma jet emerging from 14 new plasma thrusters was measured.

Table of contents
1.    The plasma thrusters tested.-
2.    The measurement system.-
3.    Test results.-
4.    Conclusions.-
5.    Some high speed video captures.-

1.    The plasma thrusters tested.-

The first plasma thruster design consisted of a high magnetic field reactor that is destroyed when discharging a high current pulse through itself.  The high electric discharge generates a strong magnetic field which compresses ions until the internal pressure of the ions surpasses the magnetic field pressure blasting and ejecting the ions at a very high speed.
In the new plasma thruster design the coil is not destroyed as less power is injected but during a longer time. The new design is also more robust and admits various discharges.

2.    The measurement system.-

Basically two speed probes were tested.

The first one based on two Langmuir probes separated about 10mm from each other and connected to a constant voltage of 40 volts through low impedance resistors and where electrically isolated:

Langmuir sensors installed on test tower

The second one consists of two Schottky photodiodes separated by 10mm and then installed after two apertures:
Schottky diodes probe
 3.    Test results.-

14 tests were made; in 12 of them the ion speed using both methods was measured.  In the first test 140 km/s was reached but in the majority of them they were between 30 and 40 km/s:
Test results

 In the following plot the photodiodes are used. The beginning of the plasma wave and its peak can be measured.  Channel 3 is connected to the photodiode nearest the Plasma Thruster, and channel 4 is connected to the next photodiode:
 
The ion speed using the Langmuir probes method was also tested.  The channel 3 is connected to the Langmuir probe pair closest  to the Plasma Thruster nozzle and the channel 4 is connected to the second one that is located about 10mm from the previous one:

4.    Conclusions.-
Both sensors measure accurately the arrival of the plasma cloud and the peak of the same.
Most of the tests were performed using the Langmuir probes because the voltage levels were higher.   We would recommend using a greater aperture in the Schottky photodiodes in order to obtain higher voltage levels.

The Schottky photodiodes measure the temperature waveform of the plasma and the Langmuir proves its ionization levels.  Both sensors are precise and can be used together.

5.    Some high speed video captures.-

 

Test 420: Plasma Thruster TDD-2

 
Test 423: Plasma Thruster TDD-4

 

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Single stage vs multistage plasma thruster electrostatic tests during Pulsotron Plasma Thruster test programme

                      Javier Luis López, Jorge Juan López, Judy Atkins. Pulsotron S.L.

Abstract
The electric field potential inside two plasma thruster configurations was tested.
 
Index Terms – Pulstron, Plasma Technology, Plasma Thrusters, Nuclear fusion, Particle accelerators, Electrostatics, Electrostatics discharge.

Table of contents
I.    Introduction    
II.    The test setup    
III.    Test results    
IV.    Conclusions    
V.    References    

I.    Introduction

In order to design plasma thrusters to be used in nuclear fusion tests it has to be decided whether it is better to use multistage or only one stage voltage acceleration.  The present work consists of measuring and comparing both configurations.

In order to design plasma thrusters to be used in nuclear fusion tests, it is needed to test if it is better to use multistage or only one stage voltage acceleration. The present works consists on measuring and compare both configurations.

II.    The test setup
A scale model of a multistage Plasma Thruster was built consisting of a long, thin cylinder and another wide in accord with the accompanying figure.  The long cylinder is covered with 5 conductive films in grey.
Then it is attached to a wider and short one that simulates the electron source.
Image

                                                                   Multistage configuration

The short cylinder that simulates the electron source and is also covered with a conductive tape.
It is connected to a power supply of different voltages as can be seen in the diagram.  The voltage difference between successive stages is the same.

In a second configuration the main body grey plates are connected to the same voltage:

Image

Monostage configuration

The body length of the main tube was 350mm.  The hot wire distance to the body was 110mm diameter.
Image

The main body dimensions were 350mm long and 110mm diameter and the short wide section that simulates the hot wire is 2cm in length and 210mm in diameter.

The electric field potential was measured along its axis (Y=0) and close to the inner surface of the body at Y=40mm from the axis.

III.    Test results
The measured voltage was:
Image

Here is the resulting plot:
Image

As can be seen in the monostage configuration measurements, there is a plateau between 80 and 300mm where ions cannot be accelerated.
Nevertheless in the 5 stage configuration the voltage field drops at a constant rate.
Image

IV.    Conclusions
 
Multistage configuration allows a constant acceleration of ions along the tube, then a bigger difference of voltage between ion inlet and the electron source is allowed.
In the monostage configuration there is a lack of acceleration in about 2/3 of the tube.  This is a big disadvantage because the lack of acceleration generates less ion speed being less affected by the magnets outside the thruster, so such ions could erode the internal face of the ion thruster.  There is also a lot more abrupt difference of voltage between the inner tube extreme and the electron generator, so it will be necessary to apply less voltage to avoid direct electron discharge.

V.    References
    IEPC-2007-110 Status of the THALES High Efficiency Multi Stage Plasma Thruster development for HEMP-T 3050 and HEMP-T 30250 N. Koch*, H.-P. Harmann, G. Kornfeld

 

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2014-May Multimegawatt Plasma Thrusters Pulsotron-2 test report

Javier Luis López Segura,
Jorge Juan López,
Judy Atkins
Pulsotrón SL  

Abstract.-
Cuenca, in the May 2014 test campaign not only ion-heating plasma thrusters were tested but also various new electrodeless magnetic neutral beam plasma thrusters.
The average injected power ranges from 20 to 120 megawatts.
New plasma diagnostics specialized to measure the new devices were also tested.

Table of contents
1.    New electrodeless plasma thrusters design.-   
2.    Equations   
3.    Test results.-
4.    Drawbacks  
5.    Conclusions.-
6.    References.- 

7.    Some high speed video captures.- 

1.    New electrodeless plasma thrusters design.-

The new plasma thrusters are electrodeless in order to avoid the great erosion from plasma that was observed in the April test campaign.

Image

Three short plasma thrusters and one long one were built over a thick copper protection material in order to anticipate the high plasma pressure.
2.    Equations
In the next figure, the magnetic field at a distance D and an angle θ is:

Image

3.    Test results.-
The first 4 tests were calibration tests that were performed mainly in order to adjust the diagnostics and oscilloscope scale.
PT2,3 and  8 are old ion heating Plasma thrusters
PTC-1,2,3 are new electrodeless magnetic plasma thrusters
PTB-1 is a modified magnetic plasma thruster that uses a variable magnetic coil that moves the magnetic field accompanying the plasma wave

Image

The following columns represent:
1.    Column 1 represents the average current injected
2.    Megawatts injected
3.    Percentage of the injected energy. The percentage of energy not injected does not signify losses but means a lesser power thrust.
4.    Radiation losses due to Bremsstrahlung radiation
5.    Energy efficiency:  Obtained by substraction of the losses from injected energy.
6.    Relation of speed of particles measured with respect to the maximum theoretical speed.  The values are low due to the fact that the test was performed at atmospheric pressure.  The results obtained are approximate due to the problems we had with the diagnostics as is said in the Drawback chapter.
7.    The last column represents the average internal magnetic field during energy injection test.  This column does not affect the tests on plasma thrusters without magnetic compression nor the calibration tests.

Some particles reached 1.2 million metres per second as can be seen in the following plan,  reaching in the second probe at a distance of 25mm from the first one in only 13 nanoseconds.
Image
4.    Drawbacks
Diagnostics failed to measure the particle speed with acceptable accuracy due mainly to wrong grounding of the test probes and the great electromagnetic noise.  It is clear that the diagnostics methods used before do not work properly in the new plasma thrusters.

5.    Conclusions.-
The new electrodeless magnetic thrusters are much more efficient than the ion heating ones, thanks to the fact that they have less losses due to radiation and can also be used for much longer periods of time as the magnetic field prevents the nozzle erosion by plasma particles.

6.    References.-
– none –

7.    Some high speed video captures.-
Image

Test 410: Plasma Thruster PTC-3

Image

Test 411: Plasma Thruster PTB-1

 

 

 

 

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2014-April Pulsotron-2 test report

Javier Luis López Segura
Judy Atkins
Abstract.-
Cuenca, in the April 2014 test campaign the pressure ignition conditions were reached once again. Refurbished “RBR” plasma temperature sensors with enhanced shielding were used to measure Plasma performance.
New Plasma Thrusters to be used in nuclear heavy or light particles bombardment fusion and also in spacecraft propulsion were tested.
High speed particle measurement systems that can be used to measure plasma dimensions and ion temperature were tested.
It was tested high speed particle measurement systems that can be used to measure plasma dimensions and ion temperature
A new ignition system for improving the efficiency of classical gas engines was tested.

Table of contents
1. Plasma pressure test results.-
2. Plasma temperature and speed measurements.-
3. Plasma thruster test
4. Gas engine ignition system test
5. Radiation sensor
6. Conclusions.-
7. References.-
8. Some high speed video captures.-

1. Plasma pressure test results.-
The maximum pressure of High Pressure Plasma was obtained. The pressure was measured with the same method and used in the same way as that used during Pulsotron verification [9] with the following results:
a1
Plasma pressure tests result

As can be seen, most of the targets reached 1015 Pascal pressure.
The results were compared with other fusion machines, also some war heads as can be seen in references [1] to [6]

2. Plasma temperature and speed measurements.-
We used RBR sensors according to paper reference [7] but the reflective scintillator filter in form of a needle [8]
X rays emission peaks could be confirmed , without signal noise as long as the sensor was electrically isolated:
a2-1
In channel 2 the output radiation was measured using a photoelectric sensor at 1.60m from the target
In channel 3 the output radiation is measured by using an RBR sensor at only 10mm from the target
In Channel 4: the output pulse is measured at 12mm from the target by using a voltage probe.
Then it can be seen that the injection begins at mark “1”, then both radiation sensors begin to measure
On reaching mark “2” when the plasma is broken, it can be seen that the HPM begins to emit out of range of sensor at CH2, in the x rays and UV range , then the radiation sensor at CH2 reduces its inclination a little as long as this sensor does not work at far UV and X rays radiation.
Then at mark “3” the front wave of the plasma blast is detected.
a2-2
3. Plasma thruster test
A Plasma thruster was built according to the following drawing:
a3-1
Where M is the molecular weight in kg/mol (0.029 for copper)
R=8.314 J/mol K
T in kelvin

For plasma temperature of 120eV vrms = 34600m/s. The basic idea is to heat the matter to a high temperature and then it is expanded away from the nozzle.
a3-2
It is designed for 150 kilowatts output power without nuclear fusion and between 20 and 50 times higher with nuclear fusion.
As a result the test tower was dismantled due to the fact that it obtained too high power thrust, but power efficiency was low because a great part of the Pulsotron power was lost as radiation.
a3-3
Plasma emission power
The output power of plasma thrusters – 1 and 4 was 18.7 and 22 Megawatts respectively and the plasma output speed was almost double that of the previous version from 0.9 to 1.95 km/s which is still far from the maximum theoretical speed.
4. Gas engine ignition system test

a4-1
The past year a new ignition system was tested to increase gas engine efficiency by at least 10%. Unfortunately the tests failed. Then we redesigned the ignition system and added an additive to the fuel oil. As a result the greater part of the fuel was burned within 150 microseconds as it can be seen in the following oscilloscope plot:
a4-2
5. Radiation sensor
A radiation sensor was tested using an RF Schottky diode that works up to 6 gigahertz that was connected to a specially designed RF wideband antenna. As a result no radiation was detected. It must be due to the good performance of the RF design of the Pulsotron
6. Conclusions.-
Once again Pulsotron – 2 reached pressure ignition conditions in all the successful targets.
Plasma thruster works well at high power but the design must be reviewed to include magnetic propulsion instead of working at high temperature.
Gas engine ignition system works at a very high performance and can be included not only in F1 cars but also in any other oil powered engines. It can also power aircraft flying at high altitude.
7. 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] 2014, High speed reflective scintillation broadband “RBR” sensors for Pulsotron, other Z -pinches and high power laser uses, J. Lopez , Chris Costa, Jorge Lopez

[8] 2014, Z-pinch high power needle filter, J. Lopez , Chris Costa, Jorge Lopez

[9] 2014, Pulsotron-2 ignition conditions verification, J. Lopez , Chris Costa, Jorge Lopez

8. Some high speed video captures.-

a8

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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

 

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Plasma Temperature and Radiation in Tokamak, ICF, HIF and Pulsotron

Javier Luis López Segura, Pulsotron
Leila Gholamzadeh, University of Yazd

Abstract
Madrid Spain, March 2014. It is defined the maximum temperature of plasma and its radiation as a function of injected energy and confinement time in different fusion machines

Description
In the present paper the plasma temperature and its radiation are described using the Stefan Boltzmann law.

According to the Stefan Boltzmann law the radiation power is:

Image

Where:

P is output power in watts
S is the plasma surface
σ is Stefan-Boltzmann constant that is 5.67E-08 W/(m2 * K4)
T is the plasma temperature in Kelvin degrees
K is the emissivity coefficient that is between 0 and 1

If we change P by E/t where E is in watts-second or joules where t is the confinement time we will obtain that:

Image

So in order to heat the plasma we will need to increase injected energy, reduce the confinement time and also the plasma surface and the emissivity coefficient.

Input data
According to ITER tokamak public data [2], it will work at 15 keV that is 174 million degrees Kelvin, plasma surface is 680 m2 and the injected energy 500MW.

Using Formula – 2 , the maximum allowable temperature for ITER plasma will be 1900ºK that is 0.16 electronvolts.

Then according to the formula-1, it is calculated that a square meter of ITER would radiate 5.1973E+25 watts, that is similar to the output power of the entire Sun.

A rework will be needed and use of electromagnetic directional heating or other unconventional heating to solve this issue if it is possible.
– Inject deuterium frozen pellets it is totally useless as long as frozen pellets energy is negative unless throwing them at very high speed making holes in the ITER chamber –

Fortunately ICF and HIF fusion solve it in the following three ways:
– Plasma size is very reduced, also during compression it is reduced even more.
– The plasma confinement time is very short
– Also the emissivity coefficient falls drastically due to the fact that in ICF the plasma is compressed so much that the matter is so dense that it shields the output radiation

HIF fusion uses bigger lead jets, but the radiation area is reduced due to the fact that the radiation area disk wall is as thin as only one atom. It is recommended use thin flat lead jets.

Output data
As example using NIF[3], ITER[2] and HIF[4] data we obtain following approximate values:

Image

* Planned
Obtained values only can give us an idea which device is better and how it is possible to upgrade them but are not exact values as long as inertial fusion compress matter so radiation emissivity coefficient must be much lower than 1.

Conclusion
From Stefan Boltzmann point of view it is better using inertial fusion.
It is stated that target size must be reduced and compression time shortened
Also in HIF fusion it is recommended using a flat thin area in order to reduce the jet external wall.

References
[1] Stefan Boltzmann law, 1879
[2] Introduction to ITER 2011
[3] NIF status update 2013
[4] Direct drive fuel target optimization in HIF, S. Koseki, S. Kawata, Y. Hisatomi,
T. Kurosaki, D. Barada and A.I. Ogoyski, 2013
[5] Non-Uniformity of Heavy-Ion Beam Irradiation on a Direct-Driven Pellet in Inertial Confinement Fusion 2013, Leila Gholamzadeh, Abbas Ghasemizad

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Plasma Temperature and Radiation in Tokamak, ICF, HIF and Pulsotron

Javier Luis López Segura, Pulsotron
Leila Gholamzadeh, University of Yazd

Abstract
Madrid Spain, March 2014. It is defined the maximum temperature of plasma and its radiation as a function of injected energy and confinement time in different fusion machines

Description
In the present paper the plasma temperature and its radiation are described using the Stefan Boltzmann law.

According to the Stefan Boltzmann law the radiation power is:

Image

Where:

P is output power in watts
S is the plasma surface
σ is Stefan-Boltzmann constant that is 5.67E-08 W/(m2 * K4)
T is the plasma temperature in Kelvin degrees
K is the emissivity coefficient that is between 0 and 1

If we change P by E/t where E is in watts-second or joules where t is the confinement time we will obtain that:

Image

So in order to heat the plasma we will need to increase injected energy, reduce the confinement time and also the plasma surface and the emissivity coefficient.

Input data
According to ITER tokamak public data [2], it will work at 15 keV that is 174 million degrees Kelvin, plasma surface is 680 m2 and the injected energy 500MW.

Using Formula – 2 , the maximum allowable temperature for ITER plasma will be 1900ºK that is 0.16 electronvolts.

Then according to the formula-1, it is calculated that a square meter of ITER would radiate 5.1973E+25 watts, that is similar to the output power of the entire Sun.

A rework will be needed and use of electromagnetic directional heating or other unconventional heating to solve this issue if it is possible.
– Inject deuterium frozen pellets it is totally useless as long as frozen pellets energy is negative unless throwing them at very high speed making holes in the ITER chamber –

Fortunately ICF and HIF fusion solve it in the following three ways:
– Plasma size is very reduced, also during compression it is reduced even more.
– The plasma confinement time is very short
– Also the emissivity coefficient falls drastically due to the fact that in ICF the plasma is compressed so much that the matter is so dense that it shields the output radiation

HIF fusion uses bigger lead bullets, but the radiation area is reduced due to the fact that the radiation area disk wall is as thin as only one atom. It is recommended use bullets with lead disk flat and thin.

Output data
As example using NIF[3], ITER[2] and HIF[4] data we obtain following approximate values:

Image

* Planned
Obtained values only can give us an idea which device is better and how it is possible to upgrade them but are not exact values as long as inertial fusion compress matter so radiation emissivity coefficient must be much lower than 1.

Conclusion
From Stefan Boltzmann point of view it is better using inertial fusion.
It is stated that target size must be reduced and compression time shortened
Also in HIF fusion it is recommended using a flat thin area in order to reduce the bullet external wall.

References
[1] Stefan Boltzmann law, 1879
[2] Introduction to ITER 2011
[3] NIF status update 2013
[4] Direct drive fuel target optimization in HIF, S. Koseki, S. Kawata, Y. Hisatomi,
T. Kurosaki, D. Barada and A.I. Ogoyski, 2013
[5] Non-Uniformity of Heavy-Ion Beam Irradiation on a Direct-Driven Pellet in Inertial Confinement Fusion 2013, Leila Gholamzadeh, Abbas Ghasemizad

 

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