1 / 29

MURI Kick-off Meeting: Radiation Belts Topology and Remediation

This meeting will discuss the topology and remediation of radiation belts, addressing physics and technology challenges. The objective is to develop models, systems, and manpower for controlling energetic particle loss rate.

sbonita
Download Presentation

MURI Kick-off Meeting: Radiation Belts Topology and Remediation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. MURI KICK-OFF MEETINGJune 5, 2007 PARTICIPATING UNIVERSITIES UNIVERSITY OF MARYLAND, COLLEGE PARK STANFORD UNIVERSITY UNIVERSITY OF CALIFORNIA, LOS ANGELES DARTMOUTH COLLEGE VIRGINIA TECH BOSTON COLLEGE

  2. OUTLINE • Radiation Belts (RB) –Topology - Fundamentals • RB Remediation (RBR) Why? • MURI – Overarching Objectives • MURI – Methodology , Governance, Transition • MURI – Resources • The Physics of Loss Rate • Physics and Technology Challenges • Radiate, Amplify, Propagate, Precipitate • VLF Radiation from Space Transmitters • Novel ULF/VLF Radiation Concepts • ULF Injection Using Neutral Gas Releases at Orbital Speed • Rotating Magnetic Fields (RMF) • Amplification – Artificially Stimulated Emissions • Propagation – Natural and Artificial Ducts • Cyclotron Masers – Resonators and Guides – Ion Precipitation • ULF Injection in Space • Stimulated ULF Triggering and Ion Precipitation

  3. 104 >105 >106 L = 7 L = 3 L = 2 RADIATION BELTS – TOPOLOGY e-/cm2/sec , >1 MeV Inner RB 1.5<L<2, Slot 2<L<3, Outer RB L>3 Lifetime and functionality of satellites ~ Energetic particle dose Plasmapause (L~4) appears to mark transition from high to low flux of energetic particles

  4. 1 4 in in=out 2,3 out Leaky Bucket Model RB – PHYSICS ISSUES • Energetic particle flux as a function of L controlled by • Particle Injection • Radial Transport • Energization • Particle Loss

  5. Inject a bucket of water Sudden natural or artificial injection of relativistic electrons in the inner magnetosphere (e.g. by accidental or deliberate High Altitude Nuclear Detonation -HAND ) 1 4 104 in 105 106 in=out 2,3 out >108 Teq>2 yr Time to return to equilibrium depends on the size of the hole RB REMEDIATION (RBR)

  6. THE HALLOWEEN STORM FROM 1-10 NOVEMBER, 2003 OUTER BELT CENTERED NEAR L2.5 AND PLASMASPHERE WAS DISPLACED INWARDS LEADING IN NEW RADIATION BELT POPULATION IN THE SLOT AND INNER BELT. DECAY RATES DEPENDED HIGHLY ON L VALUE AND VARIED FROM 35 DAYS TO MORE THAN A YEAR BAKER AND KANEKAL 2007

  7. OVERARCHING OBJECTIVES • DEVELOP QUANTITATIVE DATA DRIVEN MODELS OF THE LOSS RATE OF ENERGETIC PARTICLES IN THE INNER MAGNETOSPHERE AND TEST AGAINST OBSERVATIONS • PROVIDE THE PHYSICS UNDERPINNINGS THAT CAN LEAD TO PRACTICAL SPACE OR GROUND BASED SYSTEMS THAT CAN ARTIFICIALLY CONTROL THE ENERGETIC PARTICLE LOSS RATE • DEVELOP THE SCIENTIFIC AND ENGINEERING MANPOWER WITH THE INTERDISCIPLINARY SKILLS REQUIRED TO ADDRESS FUTURE MAJOR TECHNICAL ISSUES OF NATIONAL SIGNIFICANCE

  8. METHODOLOGY - GOVERNANCE • TOPICS ADDRESSED BY AN INTERPLAY OF THEORY/COMPUTATION, LABORATORY EXPERIMENTS, FIELD EXPERIMENTS, SATELLITE MEASUREMENTS ANDDATA ANALYSIS • CONSORTIUM WILL OPERATE AS A COHERENT ENTITY WITH PARTICIPATING UNIVERSITIES AND ASSOCIATED GOVERNMENT LABORATORIES AND INDUSTRY PROVIDING COMPLEMENTARY EXPERTISE AND NOT AS A SERIES OF INDPENDENT PROJECTS • CONTINUOUS INTERACTION AND QUICK TRANSITION OF RESULTS TO RELEVANT DoD LABORATORIES (AFOSR, NRL) • OVERALL CONSORTIUM COORDINATION BY PAPADOPOULOS AND INAN WITH ADVICE FROM SENIOR MEMBERS – SAGDEEV, MORALES, LIU, MAGGS, MISHIN,FUNG,… • THE FORMATION OF AN EXTERNAL SCIENCE ADVISORY COMMITTEE WITH MEMBERS SUCH AS KENNEL, COFFEY, WALT, LANZEROTTI HAS BEEN RAISED WITH THE PM BUT NOT YET RESOLVED

  9. RESOURCES DEMETER HAARP LAPD CONJUGATE BUOYS DMSP WIDE RANGE OF CODES THAT COUPLE TO THE ABOVE EXPERIMENTS

  10. V|| B0  V^ trapped REQUIRES LARGE MAGNETIC WAVE ENERGY IN THE PROPER WAVELENGTH RANGE (~1-3 KM) TO BE INJECTED AND GUIDED IN THE PUMPED BELT REGION PHYSICS OF LOSS RATE • SCATTERING RATE DEPENDS ON • AMPLITUDE OF RESONANT WAVES • PRESENCE OF LARGE B GRADIENTS • PATCHES OF LARGE AMPLITUDE NON-RESONANT ES OR EM WAVES

  11. PHYSICS AND TECHNOLOGY CHALLENGES • WAVE INJECTION: • VLF INJECTION FROM SPACE BASED ANTENNAS • VLF INJECTION FROM GROUND TRANSMITTERS • ULF INJECTION FROM SPACE – NEUTRAL GAS INJECTION • INNOVATIVE INJECTION CONCEPTS - ROTATING MAGNETS • GLOBAL WAVE AMPLIFICATION • VLF AMPLIFICATION – ARTIFICIALLY STIMULATED EMISSIONS • STIMULATED ULF EMISSIONS – PROTON PRECIPITATION • GLOBAL WAVE PROPAGATION • VLF DUCTED AND NON-DUCTED PROPAGATION • ULF WAVE PROPAGATION • PHYSICS OF PRECIPITATION • WEAK VS. STRONG DIFFUSION • RELIABLE MODELING TESTED AGAINST AVAILABLE DATA (GROUND TRUTH)

  12. EFFICIENCY OF VLF RADIATION FROM SPACE-BASED TRANSMITTERS WHAT PHYSICAL PROCESSES CONTROL THE EFFICIENCY AND FAR FIELD COUPLING OF HIGH POWER, LOW FREQUENCY ANTENNAE IN A LOW DENSITY PLASMA. ELECTRIC VS MAGNETIC DIPOLES. STANFORD ANTENNA IN PLASMA AND OTHER THEORETICAL AND EMPIRICAL MODELS (SAIC, UMass) HAVE BEEN USED TO DESIGN DSX EXPERIMENT INPUT IMPEDANCE FUNCTION OF SHEATH. REQUIRES DYNAMIC TUNING NEED FOR CODE VALIDATION USE LAB EXPERIMENTS IN LAPD CHAMBER TO VALIDATE PERFORMANCE CODES FOR ELECTRIC AND MAGNETIC DIPOLES

  13. Step 1. Step 2. NOVEL WAVE INJECTION CONCEPTSNEUTRAL GAS INJECTION USE ENERGY (30 GJ/Ton) STORED IN RELEASING A LARGE AMOUNT OF LOW IONIZATION POTENTIAL GAS (e.g. Li) AT ORBITAL VELOCITY TO GENERATE THE RESONANT WAVES – GANGULI ET AL (2007) RELEASE PHOTO IONIZATION PHYSICS CHALLENGES • CONVERSION EFICIENCY FROM FREE ENERGY TO RESONANT SPECTRAL ENERGY • SATURATION LEVEL OF PRIMARY ALFVEN ION CYCLOTRON INSTABILITY – VT • WAVE CASCADE IN k-SPACE TRANSFERS ENERGY TO RESONANT REGION – UMCP • INJECTION REQUIREMENTS FOR STRONG SCATTERING – UMCP • TRAPPING OF WAVES IN MULTI-IONICBUCHSBAUM RESONANCES - DC EFFORT MAINLY THEORETICAL FEEDS DIRECTLY TO NRL – POSSIBLE CHAMBER EXPS IN OPTION PHASE

  14. How are currents generated and maintained ? Novel Antenna Concepts 17.2 c/pe 0 17.2 c/pe NOVEL WAVE INJECTION CONCEPTSROTATING MAGNETIC FIELDS RMF GENERATED EITHER BY ROTATING A PERMANENT OR SUPERCONDUCTING MAGNET OR BY PHASED ANTENNAS PHYSICS OF INTERACTION OF A RMF WITH MAGNETOPLASMA NOT UNDERSTOOD 3-D EMHD MODELING AT UMCP PARALLEL LAB EXPS AT LAPD - GEKELMAN

  15. Courtesy R. Winglee CARTOON OF CONCEPT Primary field (blue lines) Electron motion (red dots) Secondary field (red lines) B- FIELD GRADIENTS DRIVEN BY RFM • DIFFERENTIAL MOTION OF ELECTRONS AND IONS GENERATES PLASMA CURRENTS RESULTING IN INDUCED FIELD DECAYING AS 1/rn WITH n<<3 • LARGE QUASI- STATIC B- FIELD GRADIENTS CAN BREAK THE ADIABATIC INVARIANCE OF ELECTRONS AND SCATTER THEM INTO THE LOSS CONE OPTION PHASE – ASSESS INDIVIDUAL PLATFORM PROTECTION

  16. Artificially Stimulated Emissions AMPLIFICATIONArtificially Stimulated Emissions (ASE) Helliwell Stanford Siple exps COHERENT GROWTH 20-30 dB THRESHOLD SIGNAL SATURATION PHASE ADVANCE PRIOR TO TRIGGERING TRIGGERED EMISSIONS – risers, fallers, hooks ENTRAINMENT GROWTH SUPPRESSION for 2 signals with Df< 30 IMPORTANCE OF CHIRPING Probably the most serious challenge to our current understanding of nonlinear plasma physics 20-30 dB amplification major leverage to RBR

  17. ASE - ISSUES • Physics of coherent amplification and saturation • Role of chirping and optimization • Role of ducts • Physics and control of threshold – inhomogeneity, F(v),else ? • Reason for frequency shift – inhomogeneity or nonlinearity? • Is threshold related to oscillator behavior (BWO) • Is amplification affected by relativistic effects or a nuclear environment? APPROACH • Specialized codes and parallel architectures; UMCP + NRL, DC • Targeted field experiments – HAARP, Alpha transmitter; Inan • Targeted Lab experiments – TBD (Need ECRH source) UCLA

  18. CRRES orbit 766 VLF PROPAGATION - DUCTS • The perturbed plasmasphere contains field-aligned density irregularities that efficiently guide whistler waves • In addition to loss-cone distribution amplification requires the presence of ducts (field-aligned irregularities with dn/n>.01) • Model ducted propagation in inhomogeneous media and test against lab experiments (DC – Streltsov, UCLA Gekelman) • Understand and predict time and location of natural ducts (BC – Mishin) • Model and conduct field tests of artificial duct formation using F-region heating with HAARP (UMCP)

  19. Plasmaspheric Duct Formation • Analyze magnetically-conjugate observations from the Cluster and DMSP satellites to find the response time of the plasmasphere to sub-storms. • Analyze available satellite (CRRES/Cluster/IMAGE/DMSP) data to find the drivers of plasmaspheric field-aligned irregularities (FAI) and their spatial/temporal characteristics. • Conduct theoretical and numerical studies of the (sub) storm-time ring current-plasmasphere interaction resulting in the FAI (ducts) generation. • Analyze observations from Siple and HAARP to determine geophysical conditions necessary and sufficient for the formation of ducts. • 5. Develop algorithms that allow location and time of duct formation

  20. ARTIFICIAL TRANSIONOSPHERIC DUCTS • 2D MODELING SHOWS THAT TRANSIONOSPHERIC DUCTS WITH dn/n> .5 FORM IN 15 MINUTES WITH FULL HAARP F-REGION HEATING • CONDUCT 3D SIMULATIONS - UMCP • CONDUCT HAARP EXPS DIAGNOSED WITH OVERFLYING SATS (DMSP, DEMETER) AND STANFORD VLF RECEIVERS – UMCP • DETERMINE RELEVANCE OF LAB EXPERIMENT

  21. Temporal Evolution of Density

  22. SHEAR ALFVEN WAVE B Ion Cyclotron Instability Cash et al. 2006 Fabry-Perot like Resonator CYCLOTRON MASERS - RESONATORS AND GUIDES – ION PRECIPITATION

  23. MASER ELEMENTS - FEEDBACK INVERTED POPULATION LOSS-CONE • CONTROL OFCYCLOTRON MASERS BY IONOSPHERIC HEATING • TRIGGERING STMULATED ULF WAVES AND ION PRECIPITATION • INJECTING ULF POWER IN THE MAGNETOSPHERE

  24. 1. SAW – REQUIRES EJet AND D/E REGION X-MODE HEATING – OBSERVED ONLY IN NEAR ZONE, ALONG THE FLUX TUBEAND POSSIBLY CONJUGATE REFLECTION B F-PEAK D/E Region heating+ Electrojet v1 E1 Bo Shear Alfven wave IONOSPHERIC ULF GENERATION SAT 10 pT BAE BAE-UMCP

  25. 2. MSONIC WAVE – REQUIRES F-REGION O-MODE, UPPER HYBRID HEATING; INDEPENDENT OF EJet – WEAK OR NO NEAR FIELD UH heating Bo k E1 Magnetosonic Alfven Wave (compressional) IONOSPHERIC ULF GENERATION Bill Bristow UAL

  26. 1OO nT ULF POWER INJECTION IN THE MAGNETOSPHERE BAE-UMCP-STANFORD COLLABORATION ULF MODULATION O-MODE .1 Hz BETWEEN 6:47.30 AND 6:59.30. DEMETER FLYOVER DETECTED .1 Hz ACTIVITY IN THE ELECTRIC FIELD AND DENSITY BETWEEN 6:51.30 AND 6:53.00. NO DETECTION ON THE GROUND

  27. MSONIC WAVE DETECTION Courtesy of Denys Pidyachiy Stanford

  28. STIMULATED ULF EMISSION ? Stimulated Ion Precipitation ?

More Related