About Stephanie Thomas

Ms. Thomas is vice president of Princeton Satellite Systems. She is the Principal Investigator for the NASA NIAC grant supporting Direct Fusion Drive. Ms. Thomas has been with PSS since her first internship as an MIT undergraduate in 1996!

Job Opening for a Plasma Physicist

We are looking for a plasma physicist to join our staff in support our new ARPA-E contract on the Princeton Field Reversed Configuration (PFRC) experiment.

Candidates should be interested in both theoretical and experimental work in plasma physics related to nuclear fusion power generation. Familiarity with low- and high-temperature plasma diagnostics is desirable. Background on any magnetic fusion device is also desirable. The position includes:

  • Help run experiments on the PFRC-2 (located at the Princeton Plasma Physics Laboratory) and analyze data.
  • Analytical and numerical work, including MHD simulations and PiC simulations.
  • Numerical modeling of plasmas.
  • Work in other areas at PSS including control, estimation, machine learning and orbit dynamics.
  • Programming in MATLAB, Python and C/C++.
  • Write proposals and come up with new topics for proposals including SBIR and STTR proposals.

Requirements include:

  • Ph.D in plasma physics (may be a recent or 2019 grad)
  • Must be a US citizen.

If you are interested, send your resumé to info@psatellite.com

Machine Learning Recipes: 2nd Edition

Apress has released a second edition of our textbook, MATLAB Machine Learning Recipes! New chapters include Fuzzy Logic and Expert Systems. We have also expanded our discussions of Neural Networks and Multiple Hypothesis Testing. The book provides a broad overview of machine learning including topics from adaptive control and estimation. Examples include learning control of aircraft and automobile target tracking.

Our book is available from Amazon or directly from Apress!

https://www.apress.com/us/book/9781484239155

The software is available on GitHub: https://github.com/Apress/matlab-machine-learning-recipes, or you can download it from our support site:

http://support.psatellite.com/files/MachineLearning.mltbx

The software is packaged as a MATLAB toolbox, so it is easy to install and uninstall!

Interstellar Documentary and New Novel for Fusion Fans

So fusion fans, there are two new ways to see DFD explored as fusion propulsion in the popular media:

  1. The Living Universe documentary series now on Curiosity Stream
  2. The Enceladus Mission” novel now in English from Amazon

The Living Universe is both a feature film for IMAX theaters and now a four-part documentary series. We blogged about our interviews in January and the series is now available on Curiosity Stream, a service dedicated to documentaries! Episode 2,”The Explorers” features a segment on DFD narrated by PSS engineer Stephanie Thomas, in addition to discussing plasma and antimatter propulsion. Here is an article about the series from Broadway World. You need to sign up for an account on Curiosity Stream to watch, which is free for 7 days and then $3 per month.

“The Encedalus Mission” by internationally best-selling hard science fiction author Brandon Q. Morris was originally written in German, and features the DFD as the propulsion technology on a mission to study newly detected life in the Saturn system; an array of six DFDs power the spaceship.  Early reviews are favorable! The book is available in paperback or for Kindle.

Send us a comment and tell us what you think if you watch the show or read the book!

Phase II NASA STTR on superconducting magnets selected!

We are pleased to announce that our Phase II STTR proposal, “Superconducting Coils for Small Nuclear Fusion Rocket Engines,” was one of 20 selected for award by NASA in this year’s round! The full list of winners is posted on NASA’s website.

Our briefing chart prepared as part of the proposal is shown below:Briefing chart

We will be building a testbed with a split-pair superconducting coil (two windings with a gap between them) and performing experiments to assess the impact of operating the magnets in the vicinity of the FRC plasma. Applications of the technology go beyond fusion reactors, for example science payloads and high-performance motors for hybrid electric aircraft.

PSS Dress Code: What is “business casual”, anyway?

Our interns always ask us, “What’s the dress code?” Our dress code at the office is business casual – which according to Wikipedia is not that well defined! We are probably on the more casual side of business casual. Here are some guidelines:

What to wear:

  • Khakis, trousers, skirts, polos, button-down shirts, blouses, sweaters
  • Dark or colored denim trousers
  • Shorts and sandals are OK in the summer – we prefer to turn the thermostat up and save money on A/C!

What NOT to wear:

  • Ripped or faded jeans
  • Very short skirts or shorts
  • Leggings – leggings are not pants! Leggings should be treated as footless tights and always paired with dresses or tunics.
  • Camisoles/spaghetti straps – camisoles are not blouses!
  • Flip-flops or sad beat-up sneakers

Anyone working on hardware should wear closed-toe shoes and tie back long hair, as in any lab space.

A side comment: my husband is a tech executive in New York, and he wears what I call the “tech uniform” to work every day: dark jeans from Banana Republic, button-down shirt, brown dress shoes, and a navy blazer. Now, guys in tech get away with this, but probably not lawyers! As PSS is solidly in the tech regime, we definitely take a more casual approach to “business casual”!

PFRC Paper Accepted to Physics of Plasmas

Our colleague Eugene Evans of PPPL has had his paper, “Particle-in-cell studies of fast-ion slowing-down rates in cool tenuous magnetized plasma,” accepted for publication in Physics of Plasmas. The article is tentatively scheduled for the April 2018 issue. A quote from the reviewer:

The paper … is an interesting, well-written paper that uses PIC to build upon earlier direct numerical simulation methods based on molecular dynamics. The authors present a clearly written discussion of the scaling properties of slowing down theory to support their numerical studies. The authors do a very good job describing the simulation approach they take… Of particular note in the paper is the good agreement between their numerical data and the sub-thermal model even when the effective computational log(lambda) was on the order of 1…  the authors did not stop with their results but instead applied their conclusions to the FRC reactor, predicting that the neutron production rate is 100 times lower than a conventional DT Tokamak.

This paper is key to the low radiation levels claimed for our PFRC design, and hence the Direct Fusion Drive. The fast ion slowing-down is what causes the tritium and other fusion ash to exit the machine. You can view a preprint on arXiv.

We will post again once the paper is published and available from Physics of Plasmas.

Living Universe Documentary

Back in early September, PSS and PPPL were visited by a film crew from Australia. The project? Living Universe: An Interstellar Voyage, which will include a feature documentary, a 4 episode TV miniseries, and a podcast. The documentary touches all aspects of an interstellar mission, from exoplanets to astrobiology, including transportation – which is where our fusion engine work comes in. The film is in production now and the producers expect to launch in late 2018.

The PFRC experiment at PPPL is the only hardware the documentary team could find with a path to fusion propulsion! Dr. Cohen was able to run the machine for the film crew, and both Mike and Stephanie were interviewed extensively. We discussed the rocket equation and the fundamental speed of fusion products, and how DFD moderates that speed with additional propellant to produce higher thrust. For an interstellar voyage, DFD would have to be much, much lighter than we know how to make it today – but who knows what innovations in magnets are possible in the future!

How will you be able to watch the film and TV series? The film should do the rounds of museums and IMAX theaters. The TV series will be available for streaming from Curiosity Stream, a service which specializes in science, history, tech & nature documentaries. We will post an update when we have a firm release date!

 

Second DFD Patent Awarded

We are pleased to report that an additional patent has been awarded for DFD! US Patent 9,822,769, “Method and Apparatus to Produce High Specific Impulse and Moderate Thrust from a Fusion-Powered Rocket Engine”, was published on Nov. 21, 2017. It’s now available from the US patent office website!

Here is a link to the patent from the Department of Energy’s Energy Innovation Portal! The inventor on the patent are Dr. Cohen, of PPPL, and three PSS engineers: Gary Pajer, Michael Paluszek, and Yosef Razin.

Fusion Rocket Engine

The first patent, “Method to Reduce Neutron Production in Small Clean Fusion Reactors,” was issued on September 9, 2017. The patent is available on Patentscope.