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Project for Solar-Terrestrial Environment Prediction

(PSTEP) in Japan

Kanya Kusano

Institute for Space-Earth Environmental ResearchNagoya University

2016 The 4th AOSWA WorkshopAsia Oceania Space Weather AllianceI

24-27Oct., 2016, jeju, Republic of Korea

Outlook

1. Introduction to PSTEP, that is the nation-wide project of space weather and space climate in Japan

2. The study for the physics-based prediction of solar eruption

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2016/10/31

Nagoya UISEE

Institute for Sun-Earth Environmental Research

NICTNAOJISAS/JAXAENRIU EC

Kyoto URIHN

Tohoku U

Hiroshima U

JAEA

Osaka P UHyogo P U

JMANIPRJMA

Kyushu U

Chiba U

JAMSTECU TokyoRIKENMusashino A USekei U

PSTEP NetworkProject for Solar-Terrestrial Environment Prediction

• 20 Institutes & 100 Researchers• Grant-in-Aid for Scientific Research on

Innovative Areas from MEXT/Japan(2015-2019)

【Objective 1】

To answer fundamental questions of solar-terrestrial

environment: ■ The onset mechanism of solar flares

■ The mechanism of radiation belt dynamics

■ The physical process whereby the sun affects climate

【Objective 2】

To build the base for next-generation space weather

forecast system■ Useful prediction for each industrial activities

■ Physics-based assessment of severe

space weather disaster

Physics-based Prediction＋

Network Observation & HPC

2015-2019

Project for Solar-Terrestrial Environment Prediction (PSTEP) supported by a Grant-in-Aid for Scientific Research on Innovative Areas from MEXT/Japan

太陽地球圏環境予測

科学研究費補助金 新学術領域研究（研究領域提案型）

synergistic interaction

System map of PSTEP models

Solar windSUSANOO

CME injector

AR NLFF

PFSS

SEP transport

REPPU GAIA

Plasmabubbleradiation belt

Solar Dynamo Earth climate systemlong

short

GIC radio propagation simulator

WASAVIES MUSCATEnd-User Models

Sun inter-planetary magnetosphere/ionosphere/atmosphere

stability

solar wind

Magnetosphere IonosphereFAC, BBF

disturbance

CME

Global solar mag.

SEP

dose warning system

TSI, SSI

T, rho

f(v)

Flare MHD

SEPinjection

satellite charge model

UFCORINmachine learning

Prediction of Solar

Eruption

History of Flare Prediction Skill

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http://www.swpc.noaa.gov/content/solar-activity-forecast-verification

-0.20

0.00

0.20

0.40

0.60

0.80

1.00

NICT

Perfect prediction

What determines the onset of solar eruptions?

Observations

TheorySimulations

AR1115observed by Hinode

Ensemble Simulation Study of Trigger

potential field

Normal Shear Reversed Shear

Opposite PolarityRight Polarity Right Polarity

weak shear

strong shear

magnetic sh

ear a

ngle

azimuth angle of small magnetic disturbance

non-potential

potential

potential field

weak shear

Normal Shear Reversed Shear

Opposite PolarityRight Polarity

Flare phase diagram (Kusano et al. 2012)

noeruption

noeruptioneruption

Ensemble Simulation Study

Kinetic Energy

magnetic sh

ear a

ngle

strong shear

2-ribbon flares

Two Types of Triggers

Opposite Polarity Reversed Shear

Two ways to trigger eruptions

sigmoid current sheet

Opposite Polarity Reversed Shear

Observational EvidencesKusano, et al. 2012, Toriumi et al. 2013, Bamba et al. 2013

AR1115AR10930

Opposite Polarity Reversed Shear

Feedback Cycle Model

Eruptive Instability

Magnetic Reconnection

destabilizingMagnetic helicity is

transferred from shear to twisted rope

driving(pull-reconnection)

Jv

Kusano et al. 2012

Opposite Polarity

Reversed Shear

What is the critical state?

Threshold of Instability

Numerical experiments of solar eruption for the various duration of trigger field injection.

h

time

Injection of trigger flux

Point of no return

OP field

critical state

Double Arc Instability

I

𝜙𝑡𝑜𝑡𝑎𝑙

𝑇 = 𝐵 ∙ 𝛻 × 𝐵

𝐵2𝑑𝑙

𝜿 ≡ 𝑻𝝓𝒓𝒆𝒄𝝓𝒕𝒐𝒕𝒂𝒍

>𝟏

𝟖𝝅

Critical Parameter

Ishiguro and Kusano 2016 (submitted to ApJ)

magnetic twist

𝜙𝑟𝑒𝑐Normalized flux of tether-cutting reconnection

Inoue, Kusano, Hayashi 2016

NLFFF

Summary

PSTEP is the new nation-wide Japanese project for developing the synergistic interaction b/w R-and-O.

Some approach of physics-based prediction of solar eruption based on the numerical model. A positive feedback b/w instability and reconnection

must be the fundamental mechanism of solar eruption, and there are the two types of triggering processes.

We proposed Double-arc Instability as the key instability for the onset of solar eruptions, in which the critical state can be determined by k-parameter.

NLFFF model may help us to develop a new physics-based prediction of solar eruptions.

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