Wave-Particle Interaction Analyzer: Direct Measurements of Wave-Particle Interactions in the Jovian Inner Magnetosphere

Transcription

1 Symposium on Planetary Science 213 Wave-Particle Interaction Analyzer: Direct Measurements of Wave-Particle Interactions in the Jovian Inner Magnetosphere Yuto Katoh [1] and Hirotsugu Kojima [2] [1] Department of Geophysics, Graduate School of Science, Tohoku University [2] Research Institute for Sustainable Humanosphere, Kyoto University Abstract: We present a new instrumentation "Wave Particle Interaction Analyzer (WPIA)" for measurement of the energy transfer process between energetic electrons and plasma waves in the magnetosphere. The WPIA measures a relative phase angle between the wave vector and velocity vector of each particle and computes an inner product W(t), while W(t) is equivalent to the variation of the kinetic energy of energetic electrons interacting with plasma waves [Katoh et al., 213]. The WPIA will be firstly realized by the Software-type WPIA in the ERG satellite mission to measure interactions between energetic electrons and whistler-mode chorus in the Earth's inner magnetosphere. In this talk we discuss scientific objectives of the WPIA in the Jovian inner magnetosphere and propose a possible plan of implementation for direct measurements of wave-particle interactions. References: Katoh, Y., M. Kitahara, H. Kojima, Y. Omura, S. Kasahara, M. Hirahara, Y. Miyoshi, K. Seki, K. Asamura, T. Takashima, and T. Ono, Significance of Wave-Particle Interaction Analyzer for direct measurements of nonlinear wave-particle interactions, Ann. Geophys., 31, , doi:1.5194/angeo , 213.

2 Symposium on Planetary Science Kawauchi-Kita Campus, Tohoku University February 2-22, 213 Outline Direct measurements of wave-particle interactions in the Jovian inner magnetosphere: Wave-Particle Interaction Analyzer (WPIA) Y. Katoh [1] and H. Kojima [2] [1] Department of Geophysics, Graduate School of Science, Tohoku University [2] Research Institute for Sustainable Humanosphere, Kyoto University 1.Introduction 2.Science objectives of WPIA on JUICE 3.Implementation to realize WPIA 4.Summary 1 2 Breakthrough driven by the WPIA In Wave-Particle Interactions, the phase relation of waves and particle velocity vectors determines the energy flow direction [Fukuhara et al., EPS 29] : Success of the Wave-Form capture in Geotail : a particle pulse detection with a few usec accuracy will be achieved in the ERG mission Conven&onal WPIA Plasma,waves (waveform) Energy,flow par&cles (velocity,distribu&on) No,phase,informa&on No,energy,flow,informa&on Plasma,waves (waveform) Energy,flow par&cle (in,each,par&cle) Detec&on,of,phase,rela&on Detec&on,of,energy,flow Representative algorithm of the S-WPIA Waveform 3"components"selected"among E 1#,#E 2#,#E 3#,#B 1#,#B 2#,#B 3 FFT Calibra6on Mag.,Field reference Coordinate transforma6on IFFT Band"limited" spectra Physical quantity no one has seen before in space 5 Par&cle K,#α,#t Coordinate transforma6on reference Mag.,Field 6

3 ERG ---Energization and Radiation in Geospace Wave-Particle Interaction Analyzer (WPIA) Small satellite mission to Geospace A mission to elucidate acceleration and loss mechanisms of relativistic electrons around Earth during space storms. One-chip type WPIA (O-WPIA) ERG mission will - achieve comprehensive plasma observations with magnetic & electric field, wave, and particle detectors with a wide energy coverage (1eV~1MeV) to capture acceleration, transport, and loss of charged particles in Geospace - establish plasma observatory under strong radiation environment. The algorithm is implemented inside the FPGA The real time processing is realized. Launch: FY (next solar maximum) FY~ Orbit : - apogee altitude:4.7re 4Re / perigee altitude: 275km 3km - inclination 31 - spin-axis stabilized (sun oriented) Mission Life : > 1year Science Instruments: - PPE (Plasma/Particle) - electron detectors LEP-e: 12eV-2keV,MEP-e: MEP-e:5keV-8keV 1-8keV LEP-e: 12eV-2keV, HEP-e: 2keV-2MeV HEP-e:3keV-2MeV, 7keV-2MeV,XEP-e: XEP-e: 2keV-2MeV - ion detectors with mass discrimination LEP-i: MEP-i: 1keV8keV LEP-i:1eV-25keV, 1eV-25keV, MEP-i: 58keV - PWE (DC Electric Field/Plasma Waves) - electric field (DCMHz) - magnetic field (1Hz- 5kHz) - MGF (DC Magnetic Field) Software type WPIA (S-WPIA) The algorithm is realized by the onboard software. Difficulty in the real time processing High flexibility in the data processing Onboard the ERG satellite mission Software-type WPIA will be installed Strong synergy with ground-network observations, modeling studies, and international spacecraft fleet. ERG project office: ERG_adm@st4a.stelab.nagoya-u.ac.jp 7 8 Chorus generation near the magnetic equator Whistler-mode chorus CLUSTER [Katoh and Omura, 27, 211; Omura et al., 28] fp/fc=4 Fig: Chorus emissions observed by CLUSTER in the equatorial region of the inner magnetosphere ω/ωe 1. [Santolik et al., 24] Wint atofh WPIA = +2in cωthe simulation results Pseudo-measurement Pseudo-measurement of WPIA in the simulation results [Katoh et al., Ann. Geophys., 213] 14 log1( Bw /B) log1( Bw /B) 14 W (t) = qew (t) v(t) N X i 11 Wi = Wint mv d( v) dk = = qe v 12

4 Signature of the electromagnetic electron hole with the statistical significance int at h = +2 cω Pseudo-measurement of WPIA in the simulation results W W int.5. log1( Bw /B) ωtr The standard deviation of the statistical noise: Wint [Omura et al., JGR 29] -2.5 Pitch Angle : 75-8 degree Time : Ω e Pitch Angle: degree ( ) = p N ( ) W (t) = qew N X Energy [kev] (t) v(t) Energy [kev] Wi = Wint i d( v) dk mv = = qe v Objective 1: Chorus and relativistic electron acceleration Science objectives of WPIA on JUICE Chorus in planetary magnetospheres CLUSTER Jovian chorus generation and relativistic electron acceleration Ion cyclotron waves around satellites: wave excitation and ion heating Interactions between Ion cyclotron waves and relativistic electrons Chorus emissions observed by Galileo in the equatorial region of the Jovian inner magnetosphere Chorus emissions observed by CLUSTER in the equatorial region of the Earth s inner magnetosphere [Kurth et al., PSS 21] [Santolik et al., GRL 24] Objective 1: Chorus and relativistic electron acceleration Objective 2: Ion cyclotron waves around satellites Acceleration of relativistic electrons by chorus in the Jovian inner magnetosphere Excitation of Ion cyclotron waves [Horne et al., Nature Phys. 28] distribution of Jovian chorus [Katoh et al., JGR 211] 17 [Russell et al., Science 2] 18

5 B 1#,#B 2#,#B 3 "(<".3"Hz) for ICW (<.3 Hz) 1 data unit: 512 pt. x 16 bit x 3 ch = 3 kb Plasma,s individual#par8cles SGWPIA,running,on,the,DHU Wave,Analyzer among E 1#,#E 2#,#E 3#,#B 1#,#B 2#,#B 3 1 data unit: 512 pt. x 16 bit x 3 ch = 3 kb Time length: 2 msec for chorus (3 khz sampling) 4 sec for ICW (128 Hz sampling) 19 Plasma,s K : 2 byte, α: 1 byte, t: 2 byte individual#par8cles 5 byte x 5 count/s =.5 kb (per 2 ms for ele.) SGWPIA,running,on,the,DHU = 1 kb (per 4 sec for ions) Computation of W(t) and W int is Resolution B 1#,#B 2#,#Bof 3 "(<".3"Hz) time-tag NOT necessarily in real-time should be fine enough among but performed to the stored data to resolve gyro-motion E 1#,#E at 2#,#E DHU s 3#,#B 1#,#B 2# earliest,#b 3 convenience and wave phase (e.g., 1 μsec) Wave,Analyzer Memory size: Time length: 1 data unit: 3.5 kb /2 ms for chorus 2 msec for chorus (3 khz sampling) 4 sec for ICW 13 (128 kb Hz /4 sampling) sec for ICW 2 Plasma,s individual#par8cles SGWPIA,running,on,the,DHU Output of S-WPIA: Telemetry budget B 1#,#B 2#,#B 3 "(<".3"Hz) for chorus 2 byte for W int(k,pa), among N(K,PA), σ(k,pa) 1 step for energy, 1 E 1# step,#e 2#,#Efor 3#,#Bpitch 1# 2#,#Bangle 3 = 6 byte Wave,Analyzer for ICW 5 step for energy, 8 step for pitch angle, 6 ch for composition = 1,44 byte Summary We studied the feasibility of the Wave-Particle Interaction Analyzer (WPIA) by using the simulation results reproducing chorus emissions The present study clarified that the method of WPIA is useful to evaluate the energy exchange between waves and particles directly and quantitatively Necessary time resolutions studied by the present study can be achieved by the state-of-the-art system of plasma instruments The WPIA measurements should be realized in the forthcoming missions (ERG, JUICE,...) References Fukuhara, H. et al., Earth Planets Space, 61, 765, 29. Hospodarsky, G. B. et al., JGR, 113, A1226, doi:1.129/28ja13237, 28. Horne, R. B. et al., Nature Phys., 4, 31, doi:1.138/nphys897, 28. Katoh, Y. and Y. Omura, GRL, 34, L312, doi:1.129/26gl28594, 27. Katoh, Y. and Y. Omura, JGR, 116, A721, doi:1.129/211ja16496, 211. Katoh, Y. et al., JGR, 116, A2215, doi:1.129/21ja16183, 211. Katoh, Y. et al., Ann. Geophys., 31, 53, doi:1.5194/angeo , 213. Kurth, W. S. et al., Planet. Space Sci., 49, 345, 21. Omura, Y. et al., JGR, 113, A4223, doi:1.129/27ja12622, 28. Omura, Y. et al., JGR, 114, A7217, doi:1.129/29ja1426, 29. Santolik, O. et al., GRL, 31, L281, doi:1.129/23gl18757, 24. Russell, C. T., and M. G. Kivelson, Science, 287, 1998, 2. 23