NGSPM-SOTTopics III: Solar Cycles & Space Climatefor start of discussion
H. HaraNational Astronomical Observatory of Japan
2016 Sep 9Topic-III Team Members:
S. Gibson, H. Hara, K. Kusano, S. SolankiIssues for Topic-III Solar Cycles & Space Climate• It covers the science topics of the long-term magnetic
cycle activity and its impact on the space climate.
• Tentative answers for the ‘Homeworks’ in NGSPM:• Level1: Is the chromosphere the best and only target
region for the Next Generation Solar Physics?
• Partially yes for the topics of total and spectral irradiance,
but not the case for Topic-III in general.
• Measuring the flows in the convection zone (CZ) may be
more essential.

• Level2a: Has Solar-C science objective fully cover themost important ones?
• Level2b: Regarding target regions other than thechromosphere, what are the science objectives?
• The flows in the convection zone and the coupling between
the flow and magnetic field will be more essential for theTopic-III.

Solar Magnetic Activity Cycle• How are magnetic fields created in the sun? (Dynamo)• Internal flows, behavior of polar magnetic fields, and polarity
reversal at poles from out-of-ecliptic observations may beimportant.

1980

1990

2000

Year

Topics: Solar Cycle & Space Climate• Candidates:• Understanding the flow structures in CZüDifferential rotation: average over longitudes well known
from helioseismology: latitude ! = 0–60 degüMeridional flows: ! = 0–60 deg, 0.95–1.00 R⨀ well known
from helioseismology.
üOther convective thermal flows? (LS global convection wasfound?)Diff. Rotation

Meridional Flow (MF)
There is consensus in MF in the shallow
part of CZ.
MF in the deep part may be estimatedfrom HMI data in the near future.

Thompson+ 1996

Rajaguru & Anita 2015

Topics: Solar Cycle & Space Climate• Candidates:• Detection of global magnetic flux in deep CZüAcoustic anomaly only found at most upper part of CZ.
üDetection of a flow in flux tube near tachocline: was one of
the targets for Solar-C Plan-A (out-of-ecliptic mission)

Ilonidas+ 2011

Birch+ 2016

Howe+ 2000

• Location and mechanism of the alpha effect• Is the possible access to this problem is to measure thecurrent helicity in an improved condition?
( e.g. stereoscopic magnetic field measurements to reducethe 180 deg uncertainty)

Topics: Solar Cycle & Space Climate• Candidates: (continues)• Observation of surface convective features inhigh latitudes• Local dynamo near the surface and its impact
on the global dynamo

Wang, Sheeley, Nash 1990
Rempel 2014

Topics: Solar Cycle & Space Climate• Candidates: (continues)• Magnetic flux transport and flux cancellationüHorizontal flux transportüVertical flux transport:• Speed of rising flux tube in CZ• Transport from photosphere to upper layers• Formation of large-scale unipolar regions

Cameron+ 2015

Birch+ 2016

Topics: Solar Cycle & Space Climate• Candidates: (continues)• Understanding the mechanism of UV irradiance (in EPIC)• Model construction of TSI and SSI (in EPIC)• Understanding photometric low variability of the Sun toother solar-like stars
TSI(W m-2)Ermolli+ 2013

Shapiro+2013• Detection of g-mode for understanding its excitation andtravel in the Sun (and for investigating the solar core )Science topics

Tasks

Key Observations

Requirements

IUnderstanding the flow
structures in convection
zone (CZ)

Measure meridionalflows in high latitudes &in deep CZDoppler velocity
for helioseismology

Full-disk obs.

One as HMI

SDO HMISO PHI

Are the data set of
HMI good enough?

2

Search for global
convection features

Doppler velocity
Magnetic field

Full-disk obs.

One as HMI

HMI

Are the data set of
HMI good enough?

3

Observe surface
convective features inhigh latitudes

Doppler velocity
Magnetic field

FOV≳200”(SG size x n)

One as HMI

HiniodeSO PHIIs high-resol. Dopplerobs. attractive?

Acoustic anomaly inconvection zone

Doppler velocity
for helioseismology

Full-disk obs.

One as HMI

SOHO &SDO

Only found at mostupper part of CZ

Detection of a flow influx tube near tachocline

Doppler velocity
for helioseismology

Full-disk obs.

One as HMI at
L5 point forlarge-angle
helioseismology

SOHO & SDOfrom Earthside obs.

Was a target for
Solar-C Plan-A.
Is 1.3yr modulation
at deep CZ real?

4

Detection of global
magnetic flux in deep CZ

5

Instruments

Conflict withothermissions

IDQuestions

6

Location and mechanismof the alpha effectObserve small-scale
kinetic and current
helicities in thephotospherePhotosphericvector magnetic
fields

FOV≳ 300”(AR size)

One as GBO
telescope orHMI

Has been
done by GBO
HMI will do it.

Hinode were used for
current helicity. Needfurther upgrade?

7

Understand local
dynamo near thesurface and its impact on
the global dynamo

Measure kinetic andmagnetic energy insmall-scale turbulent
convection

Doppler velocity
Photosphericvector magnetic
fieldsΔx ≤ 0.1”

One as Hinode
NBF & SP

DKIST
Solar-C SUVITSO PHI?

Can knowledge at thesurface be applied tothe local dynamo indeep CZ?

GBO: Ground-Based Observatories

Conflict withothermissions

Questions

One as Hinode
NFI

DKIST
Solar-C SUVITSO PHI?

Clarify the formation& fragmentation ofmagnetic patchesΔx ≤1”

One as HMI

HMICannot be detectedby GONG?

Transport ofmagnetic flux fromphotosphere toupper layers

Photospheric andchromosphericmagnetic fields inspectropolarimetryΔx ≲0.5”

Spectropolarimeter

DKIST
Solar-C SUVIT

Need wide FOV
instrument for AR
loops?

Doppler velocity
Magnetic field

Full-disk obs.
Δx ~ 1”

One as HMI

MDI, HMI, …

Due to a mere
diffusion? Nocontribution of global
convection?

ID

Science topics

Tasks

Key Observations

Requirements

Instruments

8

Magnetic flux transportand flux cancellation

Evaluate horizontal flux
transport

Doppler velocity
Magnetic field

Δx ≤0.1” forobserving smallscale processes

Evaluate vertical flux
transport

Doppler velocity
for helioseismology
to detect rising flux
tube in CZ
Magnetic fields

910

11

Formation of large-scale
unipolar regions

What gives the size andlifetime of the unipolar
regions?

ID

Science topics

12

Understanding themechanism of UV
irradiance(a topic in EPIC)

131415Tasks

Key Observations

Requirements

Measure brightness offine scale structures in
multiple UV (200–400nm) and visual
wavelengths inmagnetized and nonmagnetized regions

High-res. UVimages
Photosphericvector magneticfields
chromo. images

Δx ≤ 0.1”
UV: 200-400 nm

Model construction of
TSI and SSI(a topic in EPIC)

Construct solar
irradiance model against
full disk magnetic fields
based on understanding
the mechanism of UV
irradianceTSI & SSI obs.
Magnetic fieldΔt≳ 3 yr ?
Full-disk obs.
Δx=NA (TSI & SSI)Δx~1”(magnetogram)

Understanding
photometric low
variability of the Sun toother solar-like stars

Measure the variabilityof photometric band
intensity

Long-term
photometory at
photometric bands
Magnetic fieldΔt≳ 3 yr ?
Full-disk obs.

Detection of g-mode forunderstanding its
excitation and travel ofwaves in the Sun (and forinvestigating the solarcore )Detect g-mode signals
near 100micro Hz andspecify the modes forfurther study

Low-noisephotometric or
Dopplerobservations of low lg-modeΔt≳ 3 yr ?
Full-disk obs.
Δx=NA

Instruments
High-res. UV
imager

Conflict withother
missions

Questions(Suunrise)

Partially possible, butdifficult for stable
observations inSunrise balloon

TSI & SSImonitors
One as HMI(SOHO)(SORCE)Not done without
any new information

photometricband obs.

Some withSO PHICan we confirm the
STARE model
prediction in the
recent study correct?

One as Hinodefast NFI andslow SP

Solar-C PlanA*Noisereduction
methodology
not yetunderstood*Somemission inEurope (suchas ASTROD)

g-mode has not been
detected by ≳10yr
SOHO observations.

Supplemental Slides

Installation Site of Science Instruments• Earth• At the best seeing site for topics of high-resolution
surface magnetic and velocity fields• Multiple points like GONG for a level of helioseismology• Space• LEO sun synchronous orbit like TRACE, Hinode, IRIS
• GEO like SDO for high-speed data link to ground; Solar-C• L1 like SOHO for full-time day condition• L5 for a large angle helioseismology; also a vantage pointfor stable imaging of ICME impact to Earth, active region
watch before appearing the view from Earth, etc.
• Out-of-ecliptic orbit like SO for access to high-latitude
regions; also a view of Sun as a star; (some except forDoppler helioseismology are possible by high-res.
telescopes from the Earth direction.)Out-of-ecliptic
SSO, GSO
L1L5

Exploration from out-of-ecliptic orbit
Toward understanding the solar dynamo• Surface magnetic activity in polar regions• Surface/internal flow fields in polar regions• Convection in polar regions• Search of tachocline regarded as a source region of strong
magnetic fields

Exploration from Vantage Point• Global and local evolution of polar upper atmosphere from newviewpoints• Total irradiance measurements from out-of-ecliptic orbit• Solar wind measurement in polar CH and Alfven wave detection
from inclined views• Imaging of CMEs and solar wind/CIR shock structures• Others
TSI(W m-2)

Target Final Orbit
SOLAR-C Plan-AEarthSun

The target orbital period of 1 yr, synchronized with EarthSOLAR-C PLAN-A: Science Questions