Astron (Christofilos)
Foundational historical experiment establishing the physics of magnetic field reversal for fusion confinement.
01 Definition
An early experimental fusion concept conceived by Nicholas Christofilos at LLNL using a relativistic electron layer to achieve magnetic field reversal.
02 Detailed_Analysis
Developed under Project Sherwood at LLNL between 1956 and 1973 by Nicholas Christofilos, the Astron concept sought to confine a hot plasma inside a closed magnetic field geometry created by an internal 'E-layer'—a circulating ring of relativistic electrons. Although the experiment achieved high-current electron injection, it was unable to achieve complete magnetic field reversal due to beam-trapping instabilities and rapid particle loss, serving as a key precursor to modern FRC and spheromak concepts.
03 Key_Facts
- ▸ Conceived by Nicholas Christofilos; operated at LLNL (1956-1973)
- ▸ First major experimental effort aimed at achieving magnetic field reversal
- ▸ Employed an internal relativistic electron beam (E-layer)
- ▸ Conceptual ancestor to modern Field-Reversed Configurations and spheromaks
04 Deep_Dive_Intelligence
Overview
Nicholas Christofilos's Astron experiment at LLNL (1956-1973). Concept: E-layer — ring of relativistic electrons in magnetic mirror to achieve magnetic field reversal. Goal: create closed field lines for compact torus confinement. NEVER achieved field reversal — the fundamental goal. Beam: 100-120 A at ~4 MeV, 0.3 μs pulses. E-layer: 60 cm dia, 300-400 cm long, >1000 A circulating current. 50% particle loss in first 100 μs. E-layers stable up to 200 ms at low pressure. Axial compression by 2x observed. Failure: E-layer buildup losses + poor trapping on later pulses. Funding cancelled 1972, wound down 1973. EARLIEST CONCEPTION OF A COMPACT TORUS — class includes Spheromak and FRC. Linear induction accelerator developed for Astron — now used in many applications. T.K. Fowler co-authored (later LLNL director). Christofilos: Greek engineer, NO formal physics credentials. Presented at 1958 Atoms for Peace conference, Geneva. Lineage: Astron → Spheromak (LLNL/PPPL) and FRC (LANL).
Entity Type: Experiment — Astron (Christofilos) is a scientific experiment or test program.
Technical Definition
A 1960s LLNL fusion experiment proposed by Nicholas Christofilos using a relativistic electron beam to create a field-reversed configuration. A direct precursor to modern FRC research.
Related Concepts: FRC, LLNL, Christofilos
Network Relationships
Astron (Christofilos) connects to 3 entities in the intelligence network:
Concepts (2):
- → Spheromak: Conceptual ancestor — compact torus
- ← Strong-Focusing Principle: Christofilos invented both strong focusing (1949) and Astron (1956)
Organisations (1):
- → LLNL: Hosted at LLNL (1956-1973)
Research Findings
Astron (Christofilos) appears in 5 research analysis documents:
AVCO PlasmaRadiationShield 1967:
Findings: AVCO Plasmaradiationshield 1967
Source PDF: [AVCO_PlasmaRadiationShield_1967.pdf](/archive/AVCO_PlasmaRadiationShield_1967)
Date range: 1955-1985
Source org: NASA
Summary
This 1967 NASA contractor report, prepared by AVCO Corporation researchers Richard H. Levy and Francis W. French, explores the concept of a P...
AVCO PlasmaRadiationShield 1967:
Findings: AVCO Plasmaradiationshield 1967
Source PDF: [AVCO_PlasmaRadiationShield_1967.pdf](/archive/AVCO_PlasmaRadiationShield_1967)
Date range: 1955-1985
Source org: NASA
Summary
This 1967 NASA contractor report, prepared by AVCO Corporation researchers Richard H. Levy and Francis W. French, explores the concept of a P...
Christofilos Astron Fusion 2011:
Findings: Christofilos Astron Fusion 2011
Source PDF: [Christofilos_Astron_Fusion_2011.pdf](/archive/Christofilos_Astron_Fusion_2011)
Date range: 1955-2011
Source org: LANL
Summary
Published in 2011 by researchers affiliated with Princeton University and the Albert Einstein College of Medicine, this review article chroni...
IAEA Fusion Research Vol2 1983:
Findings: IAEA Fusion Research Vol2 1983
Source PDF: [IAEA_Fusion_Research_Vol2_1983.pdf](/archive/IAEA_Fusion_Research_Vol2_1983)
Date range: 1956-2025
Source org: LANL
Summary
This document, published by the International Atomic Energy Agency (IAEA) in 1983, contains the second volume of proceedings from the Ninth Int...
IAEA PlasmaPhysicsFusionResearchVol2 1983:
Findings: IAEA Plasmaphysicsfusionresearchvol2 1983
Source PDF: [IAEA_PlasmaPhysicsFusionResearchVol2_1983.pdf](/archive/IAEA_PlasmaPhysicsFusionResearchVol2_1983)
Date range: 1956-2025
Source org: LANL
Summary
This 1983 publication from the International Atomic Energy Agency presents Volume II of the proceedings from the Ninth In...
Source Documents
Intelligence derived from 5 source documents:
- OSTI.gov — Astron Thermonuclear Reactor report (1958)
- PPPL — 'Greek Fire: Nicholas Christofilos and the Astron Project' (2011)
- Physics of Fluids 1973-74 — Christofilos, Fowler, Briggs, Stallard
- Wikipedia — Astron (fusion reactor)
- Christofilos Astron Fusion 2011
06 Related_Terms (3)
07 Related_Entities (8)
08 Timeline_Mentions (10)
Birth of Nicholas Christofilos
Nicholas Christofilos, the future architect of the Astron fusion project, is born in Boston to Greek parents.
personnelChristofilos Academic Graduation
Nicholas Christofilos graduates from the National Polytechnic Institute in Athens with a degree in Electrical and Mechanical Engineering.
personnelChristofilos Physics Self-Education
During the Nazi occupation of Greece, Christofilos begins a rigorous self-education in nuclear physics using German textbooks while supervising truck repairs.
personnelAstron Project Inception
Nicholas Christofilos applies for an accelerator patent, and the Astron project begins at Livermore National Laboratory focusing on relativistic electron rings.
fusion-physicsFirst Accelerator Patent Application
Nicholas Christofilos applies for a patent on an accelerator design similar to the synchrotron.
fusion-physicsChristofilos Contacts Berkeley
Christofilos sends his first letter to the University of California Radiation Laboratory (UCRL) proposing improvements to accelerator performance.
fusion-physicsChristofilos conceives strong-focusing principle for accelerators
Patented 1950. Rediscovered by Brookhaven 1952. Revolutionized accelerators. Weapons application proposed by Wilson.
defense-programsStrong Focusing Principle Conceived
Christofilos writes to Berkeley delineating the 'strong focusing' or 'alternate gradient focusing' principle, which is initially ignored.
fusion-physicsStrong Focusing Patent Filed
Christofilos files a patent application for his strong focusing invention, later granted as US Patent 2,736,799.
fusion-physicsAstron E-Layer Concept Proposed
Nicholas C. Christofilos presents the 'Astron' concept at a secret Project Sherwood meeting, proposing a closed magnetic topology created by a relativistic electron E-layer.
fusion-physics09 FAQ
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Quick_Facts
- Category
- Experiments
- Aliases
- Astron (Christofilos), astron-christofilos, Christofilos, christofilos, Astron, Christofilos Astron, Astron Experiment
- Sources
- 0
- Related Terms
- 3
- Graph Entities
- 8
- Timeline Events
- 10