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Direct Fusion Drive: Enabling Rapid Deep Space Propulsion Presented By: Stephanie Thomas

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Direct Fusion Drive: Enabling Rapid Deep Space Propulsion Presented By: Stephanie Thomas Direct Fusion Drive: Enabling Rapid Deep Space Propulsion Presented by: Stephanie Thomas DIRECT FUSION DRIVE FISO Telecon 05-29-19 ‹#› Team Members Stephanie Thomas Michael Paluszek PrincetonFUSION Charles Swanson SYSTEMS Princeton Satellite Systems 6 Market St. Suite 926 Plainsboro, NJ 08536 http://www.psatellite.com Dr. Samuel Cohen Princeton Plasma Physics Lab Plainsboro, NJ This material is based upon work supported by NASA under award No. NNX16AK28G and 80NSSC18K0040 2 DFD Vs. PFRC Field Shaping RF Heating Field Shaping RF Heating Coils Fuel Antenna Coils Fuel Antenna Mirror Coil Nozzle Coil D-3He D-3HeD-3He Fusion FusionFusion Exhaust Plume Coolant Exhaust Propellant Cool Plasma Energy Absorbed Heat and Ash Extraction Cool Energy Absorbed Ion Acceleration Plasma PFRC: Princeton Field-ReVersed DFD: Direct Fusion DriVe Configuration • PFRC with an open end • Compact toroid configuration • SOL flow rate adjusted to produce • RF heating desired thrust and Isp • FRC “in a mirror” • “thrust augmentation” • SOL flow remoVes fusion exhaust • Power AND Propulsion in one deVice 3 Why Build a Small, Clean, Fusion Reactor? PFRC will produce 1-10 MWe per mini-van size reactor, with almost no radiation. Civilian NASA and DoD Space DoD Terrestrial Distributed and remote power Deep space robotic missions The electric battlefield ⁃ Villages in Alaska Lunar/Mars settlements Small NaVal combatants Mobile and emergency power Asteroid/comet interVention Forward power ⁃ Hurricane damage, Space platform power Fusion powered drones for ex. Puerto Rico High power communications boost phase missile defense Modular power satellites ⁃ Low capital cost power plants 4 PFRC Technology: Simple, Small, Clean FRC: Field-ReVersed Configuration Enabled by new magnetic plasma heating method ⁃ Steady-state operation Simple linear array of PFRC-2 in operation at PPPL Field Shaping RF Heating magnetic coils Coils Fuel Antenna Nozzle Coil Small size permits clean operation D-3He Fusion (ultra low radioactiVity) Exhaust Plume Easily direct flow for rocket Propellant Cool engine mode Plasma Energy Absorbed Ion Acceleration Schematic of Rocket Configuration 5 5/27/19 PFRC Programmatic Support to Date MNX PFRC-1 PFRC-2 DOE 1998-2015 DOE FES 2002-2009 DOE FES 2010-2016 NIAC STTRs ARPA-E OPEN NASA 2016-2019 NASA 2017-2020 2019-2020 6 NASA Has an Interest in Small Fusion NASA Power & Propulsion Needs Deep Space Gateway in cislunar space Manned surface bases on High Power Interplanetary moon, Mars Communication missions Orbital platforms Fusion Plant Outer planet and moon missions ⁃ Landers and submarines to explore geology and search for 550 AU life Orbital Platforms observatory Near interstellar telescopes, solar graVitational lens Surface Bases Interstellar asteroid intercept Communications 3He mining & transport 7 5/27/19 Why Fusion Propulsion: Deep Space Rapid Transit What can you do with a 1-2 MW fusion engine and a 10,000 kg mission? 1 year 2 years 3 years 4 years 5 years 1 AU 5 AU 10 AU 20 AU 30 AU 40 AU 2 MW 1 MW 0.6 MW 8 Advanced Propulsion Big Picture Theoretical Maximum Delta-V 300 DFD Isp: 10198 s Structural Fraction (F): 0.02 ∆ V = u log( (1+F)/F ) max e 250 200 Nuclear Electric VASIMR Isp: 4997 s V (km/s) ∆ 150 Lambert 100 Nuclear Electric Hall Isp: 2040 s 50 Nuclear Thermal Isp: 900 s Chemical Isp: 462 s 0 0 5 10 15 20 25 30 Pluto Transfer Time (yrs) AchieVable delta-V is fundamentally limited by the structural fraction and exhaust Velocity… 9 DFD Technical & Team Videos on Website https://youtu.be/hggqVB5I95I https://youtu.be/VS4o7W3UP4M 10 DFD: Propulsion and Power in One Compact Device The engine uses RF heating to create a Field Shaping RF Heating Coils Fuel Antenna CLOSED field lines, Nozzle Coil Field-ReVersed Configuration (FRC) D-3He inside a Fusion 1-2 m magnetic mirror, producing power AND thrust Propulsion and Power in One Device The fusing plasma acts as the heating source Field Shaping Coils Nozzle Coil for cool propellant flowing outside the confinement region. This D-3He process of Fusion Exhaust thrust augmentation Plume Propellant giVes us substantial thrust Cool Energy Absorbed Ion Acceleration with high exhaust Plasma velocity! Thrust: ~5-10 N/MWf Impulse: ~10,000-20,000 s ‹#› Power and Propulsion in One Device Producing power: • Fusion deposits heat in Radiation the walls (x-rays and microwaVes) • Brayton cycle engine conVerts heat to electricity • Excess heat rejected to Heat space Brayton Engine ~60% Fraction of fusion power: Electricity Radiation Exhaust Radiation 45% 55% Exhaust Radiator ~40% 13 NIAC: Pluto Explorer Mission with DFD SingLe Launch from Earth, fly directly to Pluto with constant thrust Engine 1100 kg Radiator Area 120 m2 Radiators 250 kg FueL (D2) 7250 kg HeLium-3 0.5 kg Liquid D2 tank 2.6 m radius Gas 3He tank 0.95 m radius FueL Tanks 400 kg Put a 1000 kg spacecraft in orbit around Pluto, Lander 200 kg beam power to a Lander using opticaL transmission, Structure 300 kg return high-definition video – Orbiter 500 kg and get there in Less than 5 years! payLoad Launch Mass 10000 kg 14 NIAC Pluto Explorer Vehicle Design D, 3He Tanks under Sun Shield Lander Solar Array Optical DFD Engines Comm Radiator 15 STOP RIGHT THERE. How is a fusion drive suddenly achieVable? ‹#› DFD is DIFFERENT from other fusion reactor concepts 1. Unique heating method 2. SIMPLE configuration 3. SMALL size 4. CLEAN operation – low radiation à FRC has 10x better confinement than tokamak à FRC has 20x higher ! à FRC can contain 5x higher density These features make it uniquely suited for use in space! Unique Heating: RMF Current DriVe • Antenna currents creating rotating magnetic & electric field • Current is driven • Very efficient driVe at magnet null • Closed field lines “odd-parity” -- fields are in opposite directions on either side of machine midplane “eVen-parity” – single antenna loop; open field lines (still from an animation) 18 Simple: Linear Array of Coils Propellant Addition Electron Heating Ion Acceleration Axial Field Coils Box Coil Nozzle Gas Box Coil Exhaust Closed Field Region Open Field Open Field Region Region Separatrix SOL heating section Ash Coolant The Linear configuration means the reactor couLd be assembLed in segments and simpLy pulled apart as needed. 19 Small: DFD is REALLY small Typical tokamak reactor: • 1000-4000 MW • 60 m tall • DeVelopment in 30-50 years PFRC reactor: • 1-10 MW • 2 m diameter • DeVelopment in 5-10 years • SmaLL enough to fit on a singLe Launch vehicLe ITER research reactor Person for scale 20 Clean: D-3He can burn Aneutronic fuels Main Fusion Reaction Power ⁃ D + 3He ® 4He (3.6 MeV) + p (14.7 MeV) 98.4% + ® + Side reactions ⁃ D + D ® T (1.01 MeV) + p (3.02 MeV) 0.88% ⁃ D + D ® 3He (0.82 MeV) + n (2.45 MeV) 0.72% ⁃ D + T ®4He (3.5 MeV) + n (14.1 MeV) <0.05% T ® cooled and exhausted before it can fuse 3He ® exhausted 4He ® exhausted p ® exhausted n ® deposit energy in waLLs as heat 21 Tritium Ash RemoVal In actuality, hundreds of orbits occur before the tritium is captured on a SOL field line – time < 20 ms! In the aboVe graph, just a few orbits of each type are shown. An animation is included in our technical Video. 22 CLEAN: Ultra low radiation 23 DFD is DIFFERENT than other fusion concepts Simple Small Clean • Linear array of • Plasma radius • D-3He fuel magnets ~25 cm • Exhaust tritium • EasiLy directed • Engine is 1-2 m before it can fuse plume diameter • <1% power in neutrons 24 Why now? Its Faster and Cheaper to DeVelop a Small Machine Size Radioactivity AvaiLabLe FueL Complexity SmaLL FRC < 10 MW Time Cost : <$100M : < 5 years : >$10B : > 20 years Cost Time Tokamaks > 200 MW Size Radioactivity T Breeding CompLexity 25 Summary of Key Physics Points Hamiltonian code (“RMF”) showed current driVe and rapid ion and electron heating. ! PFRC-1 demonstrated rapid electron heating, stability 103 x better than predicted by MHD, and, indirectly, FRC formation PFRC-2 thus far has demonstrated 100x improVed particle confinement and stability 105x better than predicted by MHD PIC model demonstrated current driVe, field reVersal by RMFo, and excellent agreement with full x-ray EEDF 26 Computational Tools Applied Expanding plume; leading edge of the D+ plume is getting to 900 eV, Isp = 30,000 s Orbit of ion heated by RMF LSP: particle in cell; RMF: single particle; kinetic Hamiltonian Model of plasma heating and flow in SOL UEDGE: multi-species fluid model 27 Experimental Apparatus Concluded PFRC-1 a, b, c in 2011; breakthrough achieVed in FRC electron heating methods ⁃ Electron heating to > 200 eV PFRC-2 operating now ⁃ Goal is to demonstrate keV plasmas with pulse lengths to 0.3 s § Electron heating to > 500 eV ⁃ Operated with up to 40 kW power ⁃ MNX computational studies on plasma detachment Via magnetic nozzle (LSP) Major upgrades taking place under new ARPA-E OPEN grant ⁃ Higher RF and magnet power ⁃ Lower frequency to heat ions 28 Cohen/Swanson, Compact Toroid & FIF, 2017 5/27/19 PFRC-2 Experiment 29 TWO NASA PROJECTS: 1. NASA NIAC STUDY 2. NASA PHASE II STTR ‹#›30 Questions to Answer 1. Can PFRC really produce (net power from) fusion? 2. Can DFD be made to operate for long durations in space? 3. Can DFD achieVe the necessary specific power for the desired mission parameters? Our NASA work is primarily addressing questions 2 and 3; continuing work at PPPL, and our new ARPA-E OPEN grant, address question 1. 31 NIAC: Systems Analysis of the DFD Engine Electrolysis D2O Auxiliary Power O2 Unit Startup RF Generator Coil Radiator Refrigerator Gas D Box Plasma HTS Coil Blanket Coil Cooling 3He Space Thermal Conversion neutrons Bremsstrahlung Generator Synchotron Brayton Shielding Coolant Radiator Heat Engine 32 5/27/19 Typical Reactor Parameters Parameter Value The fuel ratio sacrifices some power density Fuel D-3He for lower radiation (less D-D fusion).
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