「ひので」による理解の到達点
横山央明
東京大学地球惑星
参考文献
SOLAR-B衛星提案書 1996年11月「ひので」プロジェクトミッション期間延長提案書 2011年3月「ひので」プロジェクトミッション期間延長提案書 2013年5月

Table of contents
Overview of Hinode results & What to do next.
– Chromospheric dynamics– Flares: flows and triggers– Coronal heating and solar wind
– Photospheric magnetism and flows

SOLAR-B衛星提案書1996年11月
挑戦する研究課題– 外層大気（コロナ・彩層）の加熱メカニズム– 太陽磁場の基本構造としての微細磁束管とダイナモ機構– コロナのダイナミックスとリコネクションの詳細究明

Chromospheric dynamics

Coronal transverse
waves in a prominence
Okamoto+ 2007
fine-scale threadlikestructures
oscillating in theplane of the skywith periods ofseveral minutes
Alfven waves(c.f. Ofman & Wang2008)

Chromospheric Alfvenic Waves
De Pontieu+ 2007
Alfven waves withamplitudes on theorder of 10 to 25km/s and periods of
100 to 500 sec.
energetic enough toaccelerate the solar
wind and possibly toheat the quiet corona(c.f. Okamoto &Depontieu 2011)

Chromospheric Anemone Jets

Found in active regions
Cusp-shaped structure and bright footpoint
length 1-4 Mm, lifetime 100-500s
velocity 5-20km/s ~local Alfven speed(Shibata et al. 2007;
Nishizuka et al. 2011;
talk by Singh et al. ST01A005)

Penumbral micro-jets
Ca II H movie••••••(Katsukawa et al. 2007; Jurcak& Katsukawa 2008; 2010; posterby Katsukawa ST01-A004)

FFT filtered (f>3mHz)

Small scale jet-like features are discovered in the penumbral chromosphere.
Length: 1000 - 4000km, Duration: Shorter than 1 minvelocity > several 10s km/s, beyond the sound speed (~10km/s)
Observed everywhere above the penumbra
following the orientation of the background field
Corresponding downflows

Quiescent prominence dynamics
Berger+ 2008; 2010
filamentary downflows and vortices
dark, episodic upflows: 170-700 km in width, exhibit turbulent flow
and rise with constant speeds of 20km/s from the base toheights of 10-20 Mm. resemble buoyant starting plumes

Chromospheric dynamics: summaryWaves
Transverse waves found in prominences (Okamoto+ 2007), spicules(De Pontieu+ 2007), photospheric flux tubes (Fujimura & Tsuneta 2009),
jets (Nishizuka+ 2008)...
Evidence of the resonant-absorption thermalization (Okamoto+ 2007)
Chromospheric reconnection
Anemone jets (Shibata+ 2007), penumbral micro-jets (Katsukawa+2007)
 Ubiquitousness of magnetic reconnection, magnetic reconnection inpartially ionized plasmas (e.g. Leake+ 2013), and/or in partialcomponent asymmetric (e.g. Nakamura+ 2012)
Spicules“Type-I”, “Type-II” (mis?)understanding (De Pontieu+ 2007; Zhang+2012) need further study for mechanism
Prominence internal flows
Turbulent flows inside (Berger+ 2008; 2010)
 Magnetic Rayleigh-Taylor instability (Hillier+ 2012)

Flares and coronal activity

Flare loop flows
Yokoyama & Shibata 2001

Reconnection flows in a flare
Hara+ 2011
– Loop top hot source: 12MK, 1e10/cm^3, dV~100km/s, V~30km/s– a fast jet nearby: 200km/s: V>200km/s– inflow: 1.2MK, 2.5e9/cm^3, 20 km/s
– reconnection rate 0.05-0.1

Magnetic field structures
triggering flares
Kusano+ 2012
two types of small mag. structures
favor the onset of eruptions

Alfven waves in solar X-ray jets

Cirtain+ 2007
– x-ray jets have two distinct velocities: one near the Alfven speed( ~ 800km/s) and another near the sound speed (200km/s)

Flares and coronal activities: summary
Flows
Reconnection outflows & inflows observed (Hara+ 2011; 2014)
Shocks not yet.
(SDO/AIA observations; e.g., Takasao+ 2012; Su+ 2013)

Nonthermal aspects
 not so much addressed yet (e.g. Minoshima+ 2009)
Trigger
Kusano+’s (2012) model, Observationally supporting evidence(Bamba+ 2013; Toriumi+ 2014)
 Not sufficient condition ? Sigmoids unrelated ?

Force-free modeling of active region magnetic field Issues became clear: photosphere-to-corona interfaces (DeRosa+2009; Schrijver+ 2008)

Coronal heating and solar windCoronal heating:
1D simulations
Antolin+ 2008
(c.f. Moriyasu+ 2004)

Alfven wave heating modelSuzuki & Inutsuka 2005; Matsumoto & Suzuki 2012

Motions in EUV coronal loops
Hara+ 2008-- upflow motions of tens of km/s
and enhanced nonthermalvelocities near the footpoints-- near the limb, both upflows andnonthermal velocities decrease-- suggest unresolved high-speed
upflows

Outflows from the edge of an active region

Sakao+ 2007
– a pattern of continuous outflow of SXR emitting plasmasalong open field lines– mass loss rate that amounts to ~1/4 of the total mass loss
rate of the solar windOutflows from the edge of an active region

Harra+ 2008
– The Doppler velocity ranged between 20 and 50 km/s
– From the model coronal magnetic field, the outflow speeds
adjusted for LOS effects can reach over 100 km/s.

High temperature active region loops
Warren+ 2011– at the apex of the hi-temp. loops, emission measure
distribution is strongly peaked near 4MK– SXR intensity constant over 6hr– do not show cooling loops in the core of AR– suggest high-frequency heating scenario where heating
events occur on timescales much less than a cooling timePhotospheric properties of coronal loops
Kano+ 2014
– magneticfilling factor in the network is anti-correlated withthe horizontal random velocity– flux tube width of ~77 km, horizontal flow at ~2.6 km/s
– No significant difference between warm (EUV) and hot (Xray) loops in the magnetic properties or in the horizontal
random velocity at their footpoints

Energy dissipation of Alfven waves in a polar
coronal hole
Hahn & Savin 2013

Quiet corona
Warren & Brooks 2009; Brooks+ 2009
existence of universal DEM peaked near 1MK

Roots of coronal heating in the chromosphere
De Pontieu+ 2009
– moss regions, root of hot loops– upflows with velocities that are
similar (50-100km/s) fortemperatures from 0.1 to severalMK– upflows are spatiotemporallycorrelated with and and have
similar upward velocities as coolspicules (0.01MK)– mass supply driven from below inthe chromosphere(c.f. De Pontieu 2011)

Chromospheric origin of heating in quiet
regions ?
De Pontieu+ 2011; Mcintosh+ 2011
Ubiquitous mass supply upward by spicules and much of theplasma heated to temperatures between 0.02 and 0.1 MK and asmall but sufficient plasma heated above 1MK.

Coronal heating: summary 1/2
Active region EUV warm loops
Upflows (~ 100km/s) and line broadenings near footpoints (Hara+ 2008)
 Nanoflare heating localrized near footpoints, Spatially unresolved
Active region X-ray hot loops
Steady in intensity, DEM peaked at 4 MK (Warren+ 2011) Nanoflare heating uniformly distributed, high-frequency (w/ waiting timeshorter than cooling time)
Slow solar wind
Flows from an active region edge (Sakao+ 2007; Harra+ 2008; Doschek+ 2008)
Coronal holes
Line width decay < (background electron density)^(1/4) (Hahn & Savin 2013)
 Alfven wave heating
Fast solar wind
Mass supply by solar jets (Cirtain+ 2007); Acceleration by Alfven waves (Suzuki& Inutsuka 2005; Matsumoto & Suzuki 2012)

Coronal heating: summary 2/2
Quiet regions
Universal DEM peaked at 1MK (Brooks+ 2009)  mechanism ???
Alfven wave ? (AIA results by McIntosh+ 2011)
Mass supply from chromosphere, correlation w/ spicule activities (DePontieu+ 2009; 2011). Proposed the chromospheric driven heating.
 Not direct evidence, I suppose.
Relation with photospheric magnetism
No clear difference between warm and hot loops (Kano+ 2014)
 Yet to be studied more carefully and extensively
TheoryAlfven wave heating model of coronal holes Suzuki, Matsumoto model; Nonlinear generation of compressivemode and turbulent cascade
Nanoflare model
 localization OK? Maybe no model yet.

Photospheric magnetism and flows

Horizontal magnetic flux of the quiet-Sun
internetwork
Lites+ 2008
horizontal apparent flux
density is 55 Mx/cm^2
vertical apparent flux density
is 11 Mx/cm^2Mag fields are organized on
mesogranular scales
unresolved structures ?
(c.f. Ishikawa+ 2008;
Centeno+ 2007; Orozco
Suarez+ 2007; Martinez
Gonzalez & Bellot Rubio2009)

Convective collapse
Nagata+ 2008
The cooling of an equipartition fieldstrength flux tube precedes atransient downflow reaching 6km/s and intensification f thefield strength to 2 kG.

Polar magnetic fields

Tsuneta+ 2008
– Vertically oriented magnetic flux tubes with field strengths asstrong as 1kG– ubiquitous horizontal fields

Power spectra of V & B on the photosphere
Katsukawa & Orozco Suarez 2012
kinetic and thermal spectra have a prominent
peak at the granular scale while themagnetic one have a broadly distributed
distribution
The power-law indices of the mag. power
spectra are close to or smaller than -1,
which suggests the total mag. energy
mainly comes from either the granular
scale mag. structures or both the granularand smaller ones contributing evenly.

Magnetic cancellation in a quiet region
Iida+ 2010
Transverse magnetic
field connecting thecanceling mag.
features and strong
long-lasting Dopplerredshift signal arefound.
Consistent withOmega-loop
submergenceSupergranulation alignment in polar regions
Nagashima+ 2011
Helioseismology by SOT

Photospheric magnetism and flows: summary
Magnetic flux in quiet regions
Dominant horizontal flux (Lites+ 2007; Ishikawa+ 2008; Centeno+ 2007; Orozco
Suarez+ 2007; Martinez Gonzalez & Bellot Rubio 2009)
 surface dynamo ? (Schuessler & Voeggler 2008)
Formation of intensive magnetic tubes
Downflow and intensification: evidence of the “convective collapse” (Nagata+2008)
Polar fields
kilo-Gauss patches, dominance of horizontal field (Tsuneta+ 2008) and its
reversal (Shiota+ 2012) information for global dynamo ?
Photospheric magneto-convection
Dependence of power-law spectra difference between B & V. Flat B spectrumwith power-law index ~ -1. (Katsukawa & Orozco Suarez 2012) suggest surface dynamo and even contribution or dominance of small scale
magnetic field
And...
Emerging flux (e.g. Cheung+ 2008), cancellation (Iida+ 2010), filament formation(Okamoto+ 2008)
Local helioseismology (Nagashima+ 2011)Table of contents
Overview of Hinode results & What to do next.
– Chromospheric dynamics– Flares: flows and triggers– Coronal heating and solar wind
– Photospheric magnetism and flows

SOLAR-B衛星提案書1996年11月
挑戦する研究課題– 外層大気（コロナ・彩層）の加熱メカニズム– 太陽磁場の基本構造としての微細磁束管とダイナモ機構– コロナのダイナミックスとリコネクションの詳細究明

What to do next ?
Chromospheric dynamics
spicules: generation, thermalization, waves ...
Flares and coronal activities
reconnection: shocks (do not exist ?)trigger: proposed model’s generality, formation of active regions,emerging flux, connection w/ below the surface
micro-, nano-flares, non-thermal aspects
NLFFF model using chromospheric mag. field
Coronal heating
Almost done, I suppose...
Relation with the energy input from the lower atmosphere
Mechanisms for quiet region heating are still open.
Theory needs for localized nano-flares at footpoints.
Photospheric magnetism and flows...

What’s further ?
Solar-C がんばりましょう
Science setups
Radiative MHD: non-LTE, partially ionized ...
Preparation for the further future:
Solar dynamo
Helioseismology
Link with• planet systems, not only solar one• other stars, young SunEnd