focus fusion

8/8/2019 Focus Fusion

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Focus Fusion refers to electricity generation using a Dense Plasma Focus (DPF) nuclear

fusion generator with hydrogen-boron fuel (pB11

).A single Focus Fusion reactors will provide

virtually unlimited supplies of cheap energy in an environmentally sound way - no greenhouse

gases, and no radiation - because the reaction of pB11 is aneutronic.

Focus Fusion faces two main technical challenges:

it requires much higher ion temperatures and plasma density-confinement time product

than Deuterium-Tritium fuel;

and x-rays produced by the reaction reduce temperatures

The Dense Plasma Focus (DPF) is a device that has been used in research for the last 40

years. It was invented in 1964 and is used in many types of research. More on the history of

the DPF and Focus Fusion.The plasma focus device consists of two cylindrical copper or

berillyum electrodes nested inside each other. The outer electrode is generally no more than

6-7 inches in diameter and a foot long. The electrodes are enclosed in a vacuum chamber

with a low pressure gas (the fuel for the reaction) filling the space between them. The plasma

focus device is shown in the figure 1 below (Image designed by Glenn Millam)

Figure 1:


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The gas use in the DPF is usually a mixture of Hydrogen and Boron. . A pulse of electricity from

a capacitor bank (an energy storage device) is discharged across the electrodes. For a few

millionths of a second, an intense current flows from the outer to the inner electrode through the

gas. This current starts to heat the gas and creates an intense magnetic field. Guided by its own

magnetic field, the current forms itself into a thin sheath of tiny filaments; little whirlwinds of

hot, electrically-conducting gas called plasma.

Plasma focus in early design have two type s of design which is Fillipov Design and Mather

Design. The different between this two design is in their geometrical appearances. To study

about the plasma, we have to know the characteristics of plasma. We can divide by three phase,

1. the inverse pinch (or lift off) phase

2. the axial acceleration phase

3. the radial compression (pinch) phase

.


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In this experiment we used high voltage which is 12kV and the capacitance is large 30F

so that it can store a large amount of energy. When triggering unit is activated,a small

explosion can be seen in few seconds. In this experiment the commons thing can be

measure experimentally is the discharge current and voltage across the electrodes. The

Rogowski coil is mounted at the back of the focus tube around the inner electrode. While

the voltage will drop across the electrode we can measure using voltage probe.


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Objective:

1. To generate Plasma

2. To study the electrical Measurement of Plasma device

3. To study the Pulse current measurement by using Rogowski Coil.

4. To study the voltage measurements by plasma focus.

5. To calibrate result of plasma focus and plasma without focus.

6. To interpret the current and voltage waveform.

7.

To determine the speed of plasma due to the axial accelerations


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Apparatus:

Figure 3

[1] Vacuum pump [8] Charger (Capasitor)

[2] Gas Inlet (Argon Gas) [9] Triggering units/Switch

[3] Plasma chamber [10] Rogowski Coil

[4] Anode [11] Voltage Probe

[5] Cathode [12] Attenuator

[6] Voltage Generator [13] Oscilloscope

[7] Dumping Switch [14] Computer

[7][8]

[13]

[9]

[1] [2]

[6]

[3]

[4][5]

[10]

[11]

[12]

[14]


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Methodology1. Plasma dense focus apparatus had been set-up as shown in figure 3.

Inside the chamber where the anode is at the center and cathode is surround the anode.

2. All unwanted gases will be suck out from the chamber as a vacuum system will beapplied to the chamber,the pressure then is maintained at 1.0 mbar.


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3. An argon gas at a constant pressure 1mbar will be introduced to the system.

4. Charge the capacitor of 30 microfarad of 12 kV voltage.

5. Triggering spark gap to trigger the electric field.


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6. Dumping switch to charge the capacitor.

7. Current is measured by using Rogoski coil.

8. Voltage is measured by the voltage probe


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9. Attenuator been put to decrease the signal by 200 times.


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10.The signal been detect by the oscilloscope.

11. Repeat the experiment by using non-focus plasma and result is recorded.


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Observation and Result:

From this graph we see a spike around the 3.40315 V and 3.5 s. The spike shows that theres a

focusing action occurs during the hot dense plasma is produced.

Graph of Voltage,(V) againts Time(s) for Plasma Focus

3.50E-06

3.40315

-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

-1.00E-05 -5.00E-06 0.00E+00 5.00E-06 1.00E-05 1.50E-05 2.00E-05 2.50E-05 3.00E-05 3.50E-05 4.00E-05

Time (s)

Voltage(V)


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While for current, there a current dip that shows focusing action is occur during the hot plasma is

produced.

Then experiment is repeated by using the non-focus plasma. The reason why we need to know

the non-focus plasma so that we can calibrate and get the value of coil constant, K.

Graph of Current,I(A) againts Time,t (s) For Plasma Focus

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

-1.00E-05 -5.00E-06 0.00E+00 5.00E-06 1.00E-05 1.50E-05 2.00E-05 2.50E-05 3.00E-05 3.50E-05 4.00E-05

Time,t (s)

Current,I(A)


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Graph of Voltage(V) againts Time(s) for None Focus Plasma

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

-1.00E-05 -5.00E-06 0.00E+00 5.00E-06 1.00E-05 1.50E-05 2.00E-05 2.50E-05 3.00E-05 3.50E-05 4.00E-05

Time (s)

Voltage(V)

a

o

e

t(

) agai

ts Time(s)

o

o

e

o

s

lasma

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

-1.00E-05 -5.00E-06 0.00E+00 5.00E-06 1.00E-05 1.50E-05 2.00E-05 2.50E-05 3.00E-05 3.50E-05 4.00E-05

Time (s)

e

t(

)


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Comparison between Plasma focus and plasma non-focus to see the different.

For current, the non-focus have larger amplitude and the period of oscillations seems to be the

same. Theres no current dip occur in non-focus plasma.

Graph Current (A) agains Time(s)

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

-1.00E-05 -5.00E-06 0.00E+00 5.00E-06 1.00E-05 1.50E-05 2.00E-05 2.50E-05 3.00E-05 3.50E-05 4.00E-05

Time(s)

Current(A)

Plasma Focus

Plasma Non-Focus


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Considering the voltage, it shown that the plasma non-focus having spike compare to the focus

plasma.

From the non-Focus plasma the coil constant K will be determined.

Graph Voltage(V) againts Time(s)

-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

-1.00E-05 -5.00E-06 0.00E+00 5.00E-06 1.00E-05 1.50E-05 2.00E-05 2.50E-05 3.00E-05 3.50E-05 4.00E-05

Time(s)

Voltage(V)

Plasma Focus

Plasma Non-Focus


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Graph of Voltage(V) againts Time(s) for None Focus Plasma

3.40E-05

0.06386

2.72E-05

0.4063

1.49E-06

1.09046

6.85E-06

-0.45301

1.49E-05

0.70831

2.13E-05

-0.10275

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

-1.00E-05 -5.00E-06 0.00E+00 5.00E-06 1.00E-05 1.50E-05 2.00E-05 2.50E-05 3.00E-05 3.50E-05 4.00E-05

Time (s)

Voltage(V)


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Six peaks are observed with different time. The table below state different V and different time.

The change in time means the period of the

Voltage

(V)

Time (s) T (s)

V1 1.09046 1.49x10-6 T3 - T1 = 1.341x10

-5

V2 -0.45301 6.85x10-6

T4 - T2 = 1.445x10-5

V3 0.70831 1.49x10-5

T5 - T3 = 1.230x10-5

V4 -0.10275 2.13x10-5

T6 - T4 = 1.270x10-5

V5 0.4063 2.72x10-5

V6 0.06386 3.40x10-5

Average T= 1.3215x10-5

To calibrate the rogowski coil. We have to know what is our angular frequency of the graph.

15

5107546.4

10319.1

22

v!!! radsxT

TT

[

For LCR discharge , since we knew C = 30F.

HxxxC

L

LC

7

652104690.1

)1030)(107636.4(

11

1

!!!

!

[

[

After we get the inductance, L we have to search for average reversal ratio,fr

!1

1n

n n

x

V

V


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31421.009046.1

71317.1

5

1

09046.1

06386.04063.010275.070831.045301.009046.1

5

1

16

1

1

1

1

11

654321

1

1

1

!

!

!

!

!

r

r

n

r

n

i

j

r

f

f

V

VVVVVVf

V

V

nf

After we get the average reversal ratio,frwe can substitute in the damping3 factor ,

078.1010319.1

31421.0lnln

5!!

(!

x

fr

E

Then we can search for current Io from the peak by using equations

Axx

xx

VIoo

5

7

63

1071.1104747.1

10301012 !!!

For damping equations:

kAexeII

xT

o1171071.1 4

)10319.1)(078.10(

541

5

!

!!

E

Imax = CVo ( 1 + fr) / t

Imax=3.142. (30 x106)(12 x10

3)(1 + 0.31421)/1.3215 x10

-5

= 112kA

The coil constant will be equal to

13

1

1 102

0904.1

10112

!!! k!

Vx

V

IK

It shown that the value of k that obtained from this experiment is slightly lower than the actual

one. This mainly because of the noise generated and the filtering the signal using a specific

software, during the experiment was carried out the signal that been produce will be transfer by

the cable to the oscilloscope. The oscilloscope are located in a small room so that they wont be


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any noise that effected. Even we protect the signal from different room they might also be noise

surround them. We then filter the noise by using a specific software that we might losing some

important reading .

Conclusions:

Plasma focus been discover. The shock is occur in micro second . During the experiment we can

see that the system generate is different with the other experiment. And the plasma occur only a

short period of time compare to plasma RF discharge.

focus fusion

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