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Pictures From New Job!

Posted: Tue Jun 13, 2017 3:11 am
by Robert Dwyer
This is not a post to show any of the progress on my fusor (that shall be coming soon, however), but I thought I might share with you a unique experience I have been blessed with as of late.

Today marked my third week being employed at the University of New Mexico's Fusion and Plasma Science Laboratory. Primarily I work with a machine called the HelCat Dual-Source Plasma Device, but I also help out with whatever is needed in the other areas that deal with microwaves and pulsed power. HelCat stands for Helicon-Cathode. We call it this because it has a helicon plasma source, and a thermionic cathode (which is currently being rebuilt). The helicon source and thermionic cathode are mounted on boths sides of the device, and can be used either one at a time or at the same time (hence the "dual-source"). There is also an ion gun mounted on the side of the system that is being used to simulate how some interstellar plasmas may interact. The gases we use are primarily Argon and Helium.

This is the body of HelCat:
This is the helicon source:
This is where the thermionic cathode is normally mounted (but has been removed for rebuilding and for the convenience of other experiments).
A lot of what we have been doing (during the time I have been employed at least), is using things like mach probes, single-tip langmuire probes, and lasers to study the plasma inside the chamber.

Langmuire probe system to be mounted:
The laser that fires into the chamber. Also you can see part of the capacitor bank for the ion gun.

As of the last few days I have also gotten to see some work done with a machine called the Sinus-6 accelerator which is being used to study high-power microwaves.

The Sinus-6:

Overall I have found myself to be very lucky to have my first job here. It is giving me hands-on experience working in a scientific enviroment, and experience with plasmas, high voltage, machining, and (something I have found I am particularly fond of) vacuum systems. Just in these first few weeks of working I have gained tons of knowledge which I know I will take with me for the rest of my career, along with knowledge and advice I can take into my fusor project. This is a priceless experience I have been blessed with. I know it is rare for a high school student to have such an opportunity so I am very thankful for it.

Anyways! I thought I might just share this experience with some of you on these forums (especially since is the place that sparked my passion for nuclear/plasma science that lead me to find this opportunity in the first place).

Re: Pictures From New Job!

Posted: Wed Jun 14, 2017 5:47 am
by Richard Hull
Thanks for sharing!! Your appreciation for the opportunity to experience the hands-on-imperative in your current environment tells volumes about your joy in learning via a form of upper level OJT. This is real learning on steroids! Continue to suppliment with a lot of self-directed education through reading as needed to further own what your hands are doing and your other senses are absorbing on the job.

It sounds like you are going to go far in your future endeavors.

Richard Hull

Re: Pictures From New Job!

Posted: Wed Jun 14, 2017 10:58 am
by Dennis P Brown
Thanks for sharing those photo's and I look forward to hearing more!

I too work in a fusion related field (direct drive laser fusion.) It is fun seeing the real world applications and issues (but not the politics, however.)

This forum and the fusor conference at Richards helped to encourage my daughter to study plasma physics at MIT - last summer she did a paid internship at the German Wendelstein 7-X Stellarator and made an important discovery relative to diverter technology.

Re: Pictures From New Job!

Posted: Thu Jun 15, 2017 12:55 am
by Robert Dwyer
I will try and keep you all updated on some of the things that are happening here. It seems plasma physics is a challenging, yet fun science to study. Plasma is a finicky thing it seems, and there is much we have yet to learn. A lot of the research we do here goes towards modelling/studying some of the instabilities within magnetically confined plasmas (like Rayleigh-Taylor instabilities), which may help those who are studying fusion in magnetic confinement devices such as Tokamaks or Stellarators.

I have also found myself taking an interest in microwave interferometry as we have begun to do more testing with that system, and hopefully by the end of the summer I can share with you some actual data on the plasma from the system.

One of the great things about this opportunity, is that it allows me to actually see a lot of the things I have read in action and applied. It is one thing to read a textbook on plasma physics, but another to understand it and apply it (I am not there yet, but on my way). I now have the chance to see with my own eyes many of the things I have read in books, and apply the knowledge hands on!

Re: Pictures From New Job!

Posted: Sun Jul 02, 2017 4:53 am
by Robert Dwyer
So I decided to upload a video to youtube of the startup of HelCat. The link is as follows:

As for more of what I have been working on with regards to HelCat, I am hoping to be able to convince my supervisor to let me begin to rebuild the thermionic cathode for the device in the following days as it is currently disassembled and nobody is working on it. If this happens I will be sure to upload pictures of the cathode's reconstruction.

Re: Pictures From New Job!

Posted: Sun Jul 02, 2017 11:05 am
by Werner Engel
Woooooow! Thanks for sharing the video! It was the first time that I saw such a ramp up process! Very impressive. What kind of ion-source was there coming from the side - you mentioned?
Congrats to your job!! I recently listend to and they had a similar configuration but did not tell how they operate it.
The Helicon source was driven with 10 MHz? What main amplifier are you using? Do you have some pictures of the Helicons RF-coil?

Re: Pictures From New Job!

Posted: Sun Jul 02, 2017 5:45 pm
by Robert Dwyer
Sadly I do not have any picture of the helicon outside of the faraday cage. I should be able to get some next week though. The ion source on the side is a coaxial plasma gun. The Helicon is driven by a 4 stage 5kW amplifier. More details on the gun and the other plasma forces can be found in this paper:
(1.37 MiB) Downloaded 136 times
There is also another paper describing the machine a bit more in depth that was published in the october issue of the AIP Review of Scientific Instruments Volume 80.

Re: Pictures From New Job!

Posted: Tue Jul 04, 2017 4:01 am
by Robert Dwyer

Today I was able to open up the faraday cage and get two pictures of the helicon with a better view of its RF windings while the machine was not in use. Here are the pictures:

Re: Pictures From New Job!

Posted: Tue Jul 04, 2017 4:30 pm
by Werner Engel
So it's nothing more than some wire arround the glas vessel, connected by some isolated wires ...?

Re: Pictures From New Job!

Posted: Tue Jul 04, 2017 8:44 pm
by Robert Dwyer
Yes! It is a basic helical antenna. There apparently has been research done into how different methods of wrapping the wire can effect the plasma, but I do not know too much about these experiments.