# Presentation: 334699

## Prospects forSolar Physics from Space

- Bernhard Fleck
- ESA Research and Scientific Support Department
- NASA/GSFC
- bfleck@esa.nascom.nasa.gov

## Previous Solar Space Missions

**OSO 1-8 (1962 - 1978)**
**Skylab ATM (1973-1977)**
- Coronal holes
- Coronal loops
- Spectral atlas
- Dynamics of the TR
**SMM (1980 - 1989)**
- Solar irradiance (ACRIM),
- Flares (Hard and Soft X-ray)
- CME’s
- UV spectral atlas, dynamics
**Hinotori (1981-1991)**
**Coronas-I (1994-1995)**
**Yohkoh (1981 – 2002)**

**Skylab SO54**

## Ongoing Missions

- Ulysses (1990 - )
- SOHO (1995 - )
- ACE (1997 - )
- TRACE (1998 - )
- CORONAS-F (2001 - )
- RHESSI (2002 - )

## Future Missions

- STEREO (2006)
- Solar-B (2006)
- SDO (2008)
- Solar Orbiter (2015)
- Particle Acceleration Solar Orbiter (PASO) (NASA Roadmap 2003-2028)
- Solar Polar Imager (NASA Roadmap 2003-2028)
- Others
- SMEX proposals (NEXUS, INSITE, ...)
- Solar Probe
- Solar Sentinels (LWS)
- Reconnection and Microscale (RAM)
- Telemachus
- Magnetic Transition Region Probe
- Solar Imaging Radio Array
- Solar Polar Imager
- Sun, Heliosphere, Earth Constellation
- Stellar Imager Seismic Probe (SISP)

## STEREO

- Principal Science Objective
- Origin and consequences of CMEs
- Mission Profile
- 2 identical S/C
- Mass: 556 kg each (dry mass)
- Volume: 1.2 m x 2.0 m x 1.5 m
- Power: 540 W
- one drifting ahead of Earth, 		          one behind (22.5o per year)
- Mission life: > 2 years
- Launch: February 2006
- Launch Vehicle:  Delta 2925-10L

## STEREO Payload

- SECCHI
- 2 white-light coronagraphs (1.25-4 R, 2-15 R)
- full sun EUV imager
- heliospheric imager: externally occulted coronagraph 		            imaging the heliosphere from 12 R to beyond Earth’s                           orbit
- SWAVES
- Interplanetary radio burst tracker
- IMPACT
- 3-D distribution and plasma characteristics of energetic particles and local vector magnetic field
- PLASTIC
- Plasma characteristics of protons, alpha particles, and heavy ions

## STEREO Spacecraft

**Deployed SWAVES **
**Electric Field Antenna**
**(3 places)**

**Deployed**
**IMPACT Boom**

**IMPACT**
**Solar Wind Electron Analyzer (SWEA)**

**IMPACT**
**Suprathermal Electron Detector**
**(STE)**

**IMPACT**
**Magnetometer**
**(MAG)**

**Deployed**
**High Gain RF**
** ****Antenna**
**(HGA****)**

**SECCHI **
**Heliospheric Imager**
**(HI)**

**SECCHI**
**Sun-Centered Imaging**
**Package (SCIP) Assy**
**(COR-1, COR-2, UVI, GT)**

**Low Gain RF**
**Antenna (2)**
**(LGA)**

**Sun Sensor (5)**

**Adapter Ring**

**Bi-fold Solar Panel**

**Inertial Measurement Unit (IMU)**

**PLASTIC Instrument**

**IMPACT SEP**

**+X is Sun direction**

## Solar-B Overview

- ISAS mission (with US and UK instrument participation) as follow-on to the highly successful Yohkoh mission
- Target launch date: September 2006
- Mission Goal
- To advance our understanding of the origin of the outer solar atmosphere, the corona, and of the coupling between the fine magnetic structure at the photosphere and the dynamic processes occurring in the corona.
- Paylod: 3 instruments
- Solar Optical Telescope (SOT + FPP)
- 50 cm, 480-650 nm, spectropolarimeter 					and filtergraph
- X-ray Telescope (XRT)
- 2 - 60Å, 1 - 2.5 arcsec resolution, full disk
- EUV Imaging Spectrograph (EIS)
- 250 - 290 Å, 1.5 arcsec spatial resolution

##   Solar-B Mission Characteristics

**  ****Solar-B Mission Characteristics**

- Orbit
- sun-synchronous polar orbit
- 625 km altitude
- 97.9o inclination
- Lifetime: > 3 years
- Mass: ~900 kg
- Power: ~1000 Watts
- Attitude control
- 3-axis stabilized
- < 1 arcsec stability (<0.02” with tip tilt mirror for SOT)
- Science data rate
- Average (after JPEG/DOCM compression): 300-500 Kbps
- Max: 2 Mbps
- Telemetry
- 4 Gbit onboard storage
- Playback at 4 Mbps over Kagoshima and Svalbard (ESA/Norway contribution)

##  Solar-B: Artists’ Impression

## Solar-B Structural Model

##       Solar-B: System Finite Element Model

**S/C BUS**

**XRT**

**FPP**

**OBU**

## Solar-B: SOT/FPP Science Goals

- Magnetic Flux Transport
- Observe how magnetic flux emerges, disperses & disappears from the solar surface, including weak intranetwork fields (B<400G)
- Determine whether magnetic field is generated in or near the surface: fast dynamo action
- Scales of Convection
- Investigate the relationship of granulation, mesogranulation, and supergranulation
- Sunspots and Active Regions
- Measure the vector magnetic field of sunspots and plage areas
- Observe the formation, dynamics & decay of entire active regions
- Upper Atmospheric Connections
- Determine the role of the surface magnetic field on the structure and dynamics of the outer atmosphere
- Solar Cycle Evolution
- Measure the effect of active regions on the solar cycle irradiance modulation

##      Solar-B: Solar Optical Telescope (SOT)PI: Takeo Kosugi (ISAS)

- 0.5 m Gregorian for 0.2” spatial resolution @ 5000Å
- Preserves image quality from 3880 – 6600 Å
- Axisymmetric design for minimal instrumental polarization
- Polarization Modulator Unit: rotating waveplate before any oblique reflection
- Tip/Tilt mirror: PZT-actuated folding mirror for image stabilization (<0.02 arcsec over range 0.02 – 20 Hz)

##     Solar-B: Focal Plane Package (FPP)PI: Alan Title (LMSA)

- BFI: Broadband Filter Imager
- Filtergrams with highest spatial and temporal resolution (interference filters)
- Data similar to G-band movies from La Palma, with perfect seeing.
- FOV: 216”  108” max (partial readout and subarea selection for faster cadences also possible)
- Common focal plane with NFI: 2048  4096 CCD: 0.053” pixels
- NFI: Narrowband Filter Imager
- Tunable birefringent filter (8-calcite wide-field elements): ~0.1Å bandwidth
- Vector magnetograph
- Data similar to the SOUP filter images from La Palma, with higher sensitivity and spatial resolution.
- FOV selectable via focal plane mask:
- 320”  160” max (some vignetting in corners) for filtergrams
- 160”  160” (and smaller subfields) for Dopplergrams and magnetograms
- Common focal plane with BFI: 2048  4096 CCD: 0.08” pixels
- SP: Spectro-Polarimeter
- Fe I 6301/6302Å lines: dual line dual polarization spectra for high precision Stokes polarimetry (<0.1%)
- Littrow design (off-axis parabolic mirror)
- Data similar to HAO ASP, with much higher spatial resolution.

##        Solar-B: Optical Schematic of SOT/FPP

**Polarization Modulator**

**Folding Mirror**

**2048 x 4096 CCD**

**Polarizing BS**

**Birefringent Filter**

**Filterwheel**

**Field** **Mask**

**Field lens**

**Shutter**

**X2 Mag lens**

**Folding Mirror**

**Folding Mirror**

**Telecentric **
**    ****lenses**

**X3 Mag lens**

**Shutter**

**Field lens**

**Filterwheel**

**Litrow Mirror**

**256 x 1024 CCD**

**Polarizing BS**

**Folding Mirror**

**Slit**

**Preslit**

**Grating**

**Folding Mirror**

**Image Offset Prisms**

**Demag lens**

**50 x 50 CCD**

_**OTA**_
_**Common**_** **_**Optics**_
_**CT**_
_**NFI**_
_**BFI**_
_**SP**_

**Dual 192 x 1024 CCD**

## Solar-B FPP Design

## Solar-B: Sample FPP Data

## Comparison of ASP and                    Filtergraph Magnetograms

**Stokes Longitudinal Magnetogram obtained with the Advanced Stokes Polarimeter at the Dunn Solar Telescope (NSO/Sacramento Peak) on 13 May 1998, created from a sequence of  Stokes spectra.  Vector magnetic field and Doppler shift maps with high accuracy are also produced from this data.**

**Longitudinal Magnetogram obtained with the SOUP Filter at the Swedish Vacuum Solar Telescope (La Palma) on 13 May 1998,  constructed from a pair of filtergrams.**
**Solar-B will make vector field maps with accuracy and sensitivity similar to the ASP’s and with spatial resolution similar to these filtergrams’.  **

## Solar-B: X-ray Telescop (XRT)PI: Leon Golub (SAO)

- High resolution broadband imaging of the corona
- Relationship: photospheric driving and coronal dynamics
- High throughput to follow coronal evolution

## Solar-B: XRT Effective Areas

## Solar-B: XRT Schematics

**Mirror Assembly**

**Metering Tube**

**Electronics**

**Camera**

## Solar-B: XRT Optical Path

- White Light

- X-RAY

- 2700 mm

##         Solar-B: EUV Imaging Spectrometer (EIS)PI: Len Culhane (MSSL)

- High throughput imaging spectroscopy (0.1 < T < 20 MK)
- 15 cm diameter primary
- Two wavelength bands of 40 Å width, each with its own optimized CCD detector
- Short wavelength centered at 190 Å
- Long wavelength centered at 270 Å
- Spatial resolution: 2 arcsec (1 arcsec pixels)
- Spectral resolution: ±3 km/s (line centroids)
- Temporal resolution: 10 s in AR, < 1 s in flares

## Solar-B: EIS Optical Layout

- Primary
- mirror

- Entrance filter in
- vacuum housing

- Slit/slot
- mechanism
- and shutter

- Diffraction
- grating

- CCD
- cameras

- Spectrometer responds
- in two wavelength ranges:
- 17 - 21 nm and 25 - 29 nm

- Multilayer coatings used
- to enhance reflectivity on
- mirror and grating

- CCDs are back-thinned
- Marconi devices with high
- EUV QE

##   Solar Dynamics Observatory (SDO)

- 1st Space Weather Research Network mission in NASA’s Living With a Star (LWS) program
- LWS Goal
- Develop the scientific understanding necessary to effectively address those aspects of the connected Sun-Earth system that directly affect life and society.
- How and why does the Sun vary?
- How does the Earth respond?
- What are the impacts on life and society?
- SDO Goal
- Understand, ideally to the point of predictability, the solar variations that influence life on Earth and humanity’s technological systems by determining how the Sun’s magnetic field is generated and structured and how this stored magnetic energy is converted and released into the heliosphere and geospace in the form of solar wind, energetic particles, and variations in solar irradiance.

## SDO Mission Objectives

- Determine how and why the Sun varies
- Understand three interlinked magnetic processes that act on different time scales:
- Solar cycle
- Active regions
- Small-scale magnetic elements
- Improve understanding of how the Sun drives global change and space weather
- electromagnetic radiation
- energetic particles
- solar wind plasma

## SDO Mission Profile

- Target launch date: April 2008 (Atlas V from KSC)
- Mission life: 5 years (10 years consumables)
- 3-axis stabilized S/C, Mass  1300 kg (250 kg P/L)
- Orbit: geosynchronous, inclined at 28.5o
- 1 ground station  simple and cheap operations
- continuous contact
- extremely high data rate (150 Mbit/s)

## SDO Payload (1/2)

- Helioseismic and Vector Magnetic Imager (HMI)
- 1”-resolution full disk Doppler velocity and line-of-sight magnetic flux images every 45 sec
- Vector-magnetic field maps every 90 sec
- Significant heritage from SOHO/MDI, with enhancements to provide higher resolution (2 4k4k detectors), higher cadence, and the addition of a second channel to provide full Stokes polarization measurements
- PI: Phil Scherrer, Stanford Univ.
- EUV Variability Experiment (EVE)
- Will measure the solar EUV irradiance from 1 to 1250 Å with unprecedented spectral resolution, temporal cadence, accuracy and precision
- 3 subsystems:
- Multiple EUV Grating Spectrograph: 40 – 1200 Å, 1 Å res., 10 sec cadence
- Optics Free Spectrograph: daily in-flight calibration of MEGS
- EUV Spectrophotometer: 1 – 50 Å and 1190 – 1250 Å

## SDO Payload (2/2)

- Atmospheric Imaging Assembly (AIA)
- 4 science telescopes - 8 science channels to simultaneously image the full solar disk over broad temperature range from 0.01 to 3 MK with high spatial resolution (0.6” pixels) and at high cadence (10 sec)
- 7 EUV channels in a sequence of iron lines an He II 304 Å
- One UV channel with 1600Å, 1700Å, white light filters
- Normal incidence optics with multilayers for EUV channels
- 4 4k4k CCD cameras
- PI: Alan Title (LMSAL)

**                       ****	****	****	****	****	****	****	****	****	**

## AIA is a key component to understanding the Sun and how it drives space weather

** ****AIA images the solar outer atmosphere: its science domain is shaded **
** ****HMI measures the surface magnetic fields and the flows that distribute it**
** ****EVE provides the variation of the spectral irradiance in the (E)UV**

##       Themes of the AIA Investigation

**      ****Themes of the AIA Investigation**

_*Energy input, storage, and release:*_ **3-D dynamic coronal structure**
- 3D configuration of the solar corona; mapping magnetic free energy; evolution of the corona towards unstable configurations; the life-cycle of atmospheric field
_*Coronal heating and irradiance:*_ **thermal structure and emission**
- Contributions to solar (E)UV irradiance by types of features; physical properties of irradiance-modulating features; physical models of the irradiance-modulating features; physics-based predictive capability for the spectral irradiance
_*Transients:*_ **sources of radiation and energetic particles**
- Unstable field configurations and initiation of transients; evolution of transients; early evolution of CME’s; particle acceleration
_*Connections to geospace:*_ **material and magnetic field output of the Sun**
- Dynamic coupling of the corona and heliosphere; solar wind energetics; propagation of CME’s and related phenomena; vector field and velocity
_*Coronal seismology:*_ **a new diagnostic to access coronal physics**
- Evolution, propagation, and decay of transverse and longitudinal waves; probing coronal physics with waves; the role of magnetic topology in wave phenomena

*The needs of each of these themes determines the science requirements on the instrument and investigation*.

## Flowdown to AIA Observing Reqs.

**Flowdown to AIA Observing Reqs.**

- Where do the observed variations in the Sun’s total & spectral
- irradiance arise, how do they relate to the magnetic activity cycle?
- What magnetic field configurations lead to CMEs, filament eruptions
- and flares which produce energetic particles and radiation?
- Can the structure & dynamics of the solar wind near Earth be
- determined from the magnetic field configuration & atmospheric
- structure near the solar surface?
- When will activity occur and is it possible to make accurate
- and reliable forecasts of space weather and climate?

- What mechanisms drive the quasi-periodic
- 11-year cycle of solar activity?
- How is active region magnetic flux synthesized, concentrated & dispersed across the solar surface?
- How does magnetic reconnection on small scales reorganize the large-scale field topology and current systems?
- How significant is it in heating the corona and accelerating the solar wind?

**1**
**2**
**3**

**4**
**5**
**6**
**7**

- 1) Energy Input
-     Storage & Release

- 2) Coronal Heating &
-     Irradiance

- 3) Transients

- 5) Coronal Seismology

- t      continuity

- logT    T coverage

- Accu-racy

- 5000 K - 20 MK

- 0.7-8 MK
- (full corona)

- multi-T obs.
- for thermal
- evolution

- Full Disk
- passage

- Days

- At least
- days  for
- buildup

- Continuous observing

- Continuous
- for
- discovery

- Active
- Regions

- Full  Disk
- +off-limb

- Active
- Regions

- >1000

- Large to study
- high coronal
- field

- >10

- Large for simul-taneous obs. of
- faint & bright structures

- >1000 in
- quiescent
- channels

**Requirement              Spatial         Temporal               Thermal                     Intensity**

**Science theme**

- Full Corona

- Majority
- of  Disk

- ~10 s

- <1 min,
- a few sec in flares

- A few sec in flares

- ~10 s

- As short
- as possible

- ~0.3

- 0.3 for
- DEM inv.

- 0.7-20 MK
- (full corona)

- ~0.3 for
- T<5MK,
- ~0.6 for
- T>5MK

- ~0.3

- ~0.5 to
- limit LOS confusion

- -

- 10%

- -

- Dynamic Range

- 40’-46’

- 10%
- for density

- 10%
- for thermal
- struct.

*Dynamic Coronal Structure*

*Thermal Structure & *
*Emission*

*Sources of  Radiation *
*& Energetic Particles*

*Material & Magnetic *
*Field Output of the Sun*

*Access to new physics*

- Field of View
- x= 1Mm

**1 4**
**2 5**
**3 6**

**    ****4**
**2    **
**3 **
**    ****7**

**    ****4 **
**2  5**
**3 **
**    ****7**

**   ****4**
**   **
**3 **
** **

**    ****4**
**    ****5**
**    ****6**
**    ****7**

- 5000 K - 20 MK

**7**

## AIA Instrument  Design Overview

**AIA Instrument  Design Overview**

- Four Science Telescopes – 8 Science Channels
-      7 EUV channels in a sequence of iron lines and He II 304Å
-      One UV Channel with 1600Å, 1700Å, white light filters
- Normal incidence optics with multilayers for EUV channels
- Secondary mirrors are active for image stabilization
- Four Guide Telescopes (GT)
- Detector is a 4096x4096 thinned back illuminated CCD
- 2.5 sec readout of full CCD
- 1 sec reconfigure of all mechanisms
-      Filter Wheels
-      Sector Shutter
-      Focal Plane Shutters
- On-board data compression
- Uses look-up tables
- Lossless (RICE) and lossy are available

##     AIA Science Telescope Optical Layout

## AIA Telescope Assembly

**AIA Telescope Assembly**

- Aperture Door

- Guide Telescope (GT)

- Science Telescope (ST)

- Camera Electronics Box (CEB)

- CEB Radiator

- CCD Radiator

- A GT is mounted to each Science Telescope

- GT Pre-Amp

- PZT strain gauge pre-amp

- Vent

- CEB is independently mounted to IM

## AIA Mounted on the IM

- Four nearly identical science telescopes
- Each ST has a dedicated guide telescope for ISS
- CEB mounts separately to the IM
- AEB is mounted within IM

- AEB (not to scale)

- AIA on the IM with doors open

## AIA FOV

- 41 arcmin FOV along detector axes
- 46 arcmin FOV along diagonal of detector
- Corners of the FOV are vignetted by the filterwheel filters

## AIA Temperature Coverage

- AIA implementation makes use of multilayer coatings on normal incidence optics with filtering to achieve desired wavelength bandpasses
- EUV wavelengths selected to observe corona at required temperatures
- AIA science objectives 1, 2, 3, 4 require that the temperature resolution be ΔlogT~0.3
- Selected lines of iron to minimize abundance effects
- Four wavelengths have not been observed with TRACE or SOHO/EIT
- One analysis technique we expect to use commonly is differential emission measure (DEM) modeling   [Channel intensities: *I**i**=**//**G**i**(T**e**)n**e**2**(T**e**)dT**e* ]

## AIA Temperature Coverage

- Dots are SOHO/CDS + Yohkoh data.  Black curve is the recovered DEM using simulated AIA responses.  The responses of the AIA channels are shown normalized to recovered DEM.

## Selection of non coronal lines

- UV channel will have three filters:  White light, C IV 1550, UV Continuum
- White light used for ground calibration
- White light used for co-alignment with HMI and other ground-based instruments
- UV filters are similar to TRACE bandpasses
- Study waves and field going into the corona as well as particle beams and conducted thermal energy coming down

- EIT 304A

- Example of a prominence observed by SOHO/EIT.  The upper chromosphere has a temperature of 60,000 K.

- 14 Sept 1999

- He II 304A
- Observes the chromosphere
- Monitor filaments
- Key driver to chemistry of the Earth’s outermost atmospheric layers

## AIA Telescopes & Wavelengths

*Looking at the AIA from the Sun*

**Instrument Module /  Optical Bench**

**+Y**

**+Z**

- Fe VIII/XX/XXIII

- Fe XVIII

- Fe IX

- Fe XII/XXIV

- He II

- Fe XVI

- Fe XIV

- 1600 C IV
- 1700 UV Cont.
- 4500 White Light

- 4

- 3

- 2

- 1

##           AIA Cadence: Normal and Special Ops

**          ****AIA Cadence: Normal and Special Ops**

- Regular cadence of 10 s for 8 wavelengths for full-CCD readouts allows observations of most phenomena, guaranteed coverage, ease of analysis (timing studies), and standardized software, compatible with HMI observations and EVE science needs.

- But fast reconnection, flares, eruptions, and high-frequency waves require higher cadence. Within telemetry constraints, partial readouts in a limited set of wavelengths embedded in a slowed baseline program, infrequently implemented, broaden discovery potential without adverse effects to LWS goals

## AIA Detector System

- CCD – 4096 x 4096, 12 micron pixels
- Well depth is >150,000 electrons
- Thinned and back illuminated for quantum efficiency at EUV wavelengths
- HMI and AIA use identical cameras and CCDs except HMI CCDs are front illuminated
- e2v has produced non-flight functioning devices
- Cooling:  Need to cool below -65C
- Dark current performance
- Mitigate loss of charge transfer efficiency due to radiation damage

## CCD QE estimates based on SXI

**CCD QE estimates based on SXI**

- AIA detector quantum efficiency is based on measurements of back-illuminated e2v devices
- Experience indicate consistent QE performance within a wafer run

## CCD Camera System

- CEB – 8 Mpixels/sec via 2 Mpixels/sec from 4 ports simultaneously
- Extension of SECCHI/STEREO cameras by RAL
- Electronic design is identical to HMI
- 14-bit ADC
- Seeking to maintain identical HMI and AIA mechanical enclosures for spares compatibility

- CEB

##   AIA Image Stabilization System

- GT analog signals are used by the image stabilization system (ISS) within the associated Science Telescope
- Photo diodes and preamp circuits are redundant
- No cross-strapping for ISS
- Design is based on TRACE
- Secondary is activated with three PZTs
- Error signal provided by guide telescope

- PZTs

##      AIA Mechanism (1 of 2)

**     ****AIA Mechanism (1 of 2)**

- Aperture Door
- Tight seal to protect entrance filters
- Particle protection
- Operates once on orbit
- Focus Mechanism
- AIA design has ±800 m range
- Moves the secondary mirror
- Based on the TRACE design
- Shutter Mechanism
- Blade diameter: 6.25 in
- Minimum exposure: 5ms
- Minimum cadence: 100 ms
- For narrow slot or medium slot exposures

- TRACE door

- Focus Mech Design

##    AIA Mechanism (2 of 2)

**   ****AIA Mechanism (2 of 2)**

- Filter wheel mechanism
- Brushless DC motor with 5 positions
- Filter aperture diameter:  55 mm (4 positions)
- Max operational time:  1s between adjacent positions
- Sets the wavelength in 3 of the four telescopes
- Aperture selector (in 193/211 channel)
- Only included in one telescope
- Brushless DC motor/half shade
- Move time: 1 s
- Blade diameter: 8.3 in
- Selects wavelength in 193/211 telescope

## AIA Observing Times

- AIA provides 10s or better cadence with two wavelength channels per telescope
- Automatic exposure control is available to adjust shutter times for flares

## The AIA team will stimulate joint observing and analysis.
Coordinated observing increases the coverage of the global Sun-Earth system (e.g., STEREO, coronagraph, wind monitors, ...), provides complementary observations for the solar field (e.g., vector field, H filament data) and its atmosphere (Solar-B/EIS spectral information). And it increases interest in analysis of AIA data.
The AIA team includes PI’s and Co-I’s from several other space and ground based instruments committed to coordination (perhaps “whole fleet months”):

EVE and HMI needs have been carefully taken into account in setting plate scale, field of view, cadence, and channel selections, and in science themes.

- Coordinated observing increases the coverage of the global Sun-Earth system (e.g., STEREO, coronagraph, wind monitors, ...), provides complementary observations for the solar field (e.g., vector field, H filament data) and its atmosphere (Solar-B/EIS spectral information). And it increases interest in analysis of AIA data.
- The AIA team includes PI’s and Co-I’s from several other space and ground based instruments committed to coordination (perhaps “whole fleet months”):
- EVE and HMI needs have been carefully taken into account in setting plate scale, field of view, cadence, and channel selections, and in science themes.

**Science Coordination**

**HVMI**

**GBO coronagr.**

**SOLIS**

**SOLAR B  EIS**

**SOLAR B FPP**

**SOLAR B  XRT**

**AIA**

**Soft X-ray images for **
**complementary T-coverage **
**in corona**

**Full-Disk:**
**Vector Field **
**Convection**

**Flows (spectra) for 3-D  **
**velocities & geometry**

**Densities + Calibration**

**Vector Field small scales**
**H******

**EVE**

**Calibration**

**STEREO SECCHI**

**2D**

**3D**

**GOES**

**CME propagation**
**High Field **
**Wind structure**

**Energetic **
**Particles**

**RHESSI**

**ACE**

**STEREO -WAVES**

**Flows (spectra) for 3-D **
**velocities and geometry**

**FASR**
**VLA**
**OVRO**

**Full-Disk Chromosphere  **
**Surface Vector Field **
**for field extrapolation**

**(Non) Thermal Particles**
**Coronal Field**

**Other **

**AIA Co-I’s**

**On SDO**

**Legend:**

##   Mission Data Flow Block Diagram

## AIA Data Flow

**AIA Data Flow**

- Incoming AIA Data(from HMI pipeline)

- HMI Magnetograms(from HMI pipeline)

- Loop Outlines

- Field LineExtrapolation

##      Estimate of Quick-Look & Science Data

- Full-Disk Movies - 0.8 Mbps **(1Kx1K intensity scaled images)**
- 10 frame/minute movies in all AIA wavelengths
- 1 frame/minute of line of sight magnetograms
- 1 frame/minute Loop Movie (overlay of AIA images)
- Active Region Movies: 8  5x5 arcmin regions - 3.6 Mbps
- 12 bit Science Data, flat field corrected, despiked, MTF corrected
- A loop composite from AIA
- A line of sight magnetogram from HMI every minute
- On-line storage requirements for Quick Look + compressed science data
- 6.5% Total Data
- Daily 49 Gigabytes
- Yearly 17.9 Terabytes
- One-line Storage for Level O data
- Daily 1.1 Terabytes (factor of 18 margin on planned cache)
- Monthly  33 Terabytes (34.5 with QL:  factor of 5 margin on planned cache)

## HMI Science Objectives

## HMI Investigation Plan – 1

- The primary scientific objectives of the Helioseismic and Magnetic Imager investigation are to improve understanding of the interior sources and mechanisms of solar variability and the relationship of these internal physical processes to surface magnetic field structure and activity.
- The specific scientific objectives of the HMI investigation are to measure and study these interlinked processes:
- Convection-zone dynamics and the solar dynamo;
- Origin and evolution of sunspots, active regions and complexes of activity;
- Sources and drivers of solar magnetic activity and disturbances;
- Links between the internal processes and dynamics of the corona and heliosphere;
- Precursors of solar disturbances for space-weather forecasts.

## HMI Investigation Plan - 2

- The **HMI Investigation** includes the HMI **Instrument**, significant data **processing**, data **archiving** and **export**, data **analysis** for the **science** investigation, and **E/PO**.

- To accomplish these science goals the HMI instrument makes measurements of:
** ****Full-disk Doppler velocity, line-of-sight magnetic flux, and continuum images with resolution better than 1.5 arc-sec at least every 50 seconds.  **
- The Dopplergrams are maps of the motion of the solar photosphere.  They are made from a sequence of filtergrams.  They are used to make helioseismic inferences of the solar interior structure and dynamics.
-  **Full-disk vector magnetic images of the solar magnetic field with resolution better than 1.5 arc-sec at least every 10 minutes.**
- The magnetograms are made from a sequence of measurements of the polarization in a spectral line.
**The sequences of filtergrams must be 99.99% complete 95% of the time**

## HMI Science Objectives

- Convection-zone dynamics and the solar dynamo
- Structure and dynamics of the tachocline
- Variations in differential rotation
- Evolution of meridional circulation
- Dynamics in the near surface shear layer
- Origin and evolution of sunspots, active regions and complexes of activity
- Formation and deep structure of magnetic complexes of activity
- Active region source and evolution
- Magnetic flux concentration in sunspots
- Sources and mechanisms of solar irradiance variations
- Sources and drivers of solar activity and disturbances
- Origin and dynamics of magnetic sheared structures and d-type sunspots
- Magnetic configuration and mechanisms of solar flares
- Emergence of magnetic flux and solar transient events
- Evolution of small-scale structures and magnetic carpet
- Links between the internal processes and dynamics of the corona and heliosphere
- Complexity and energetics of the solar corona
- Large-scale coronal field estimates
- Coronal magnetic structure and solar wind
- Precursors of solar disturbances for space-weather forecasts
- Far-side imaging and activity index
- Predicting emergence of active regions by helioseismic imaging
- Determination of magnetic cloud Bs events

## HMI Science Data Products

**HMI Science Data Products are high-level data products which are required for input to the science analyses.  These are time series of maps of physical quantities in and on the Sun.**
- Internal rotation Ω(r,Θ) (0<r<R)
- Internal sound speed, cs(r,Θ) (0<r<R)
- Full-disk velocity, v(r,Θ,Φ) and sound speed, cs(r,Θ,Φ) maps (0-30Mm)
- Carrington synoptic v and cs maps (0-30Mm)
- High-resolution v and cs maps (0-30Mm)
- Deep-focus v and cs maps (0-200Mm)
- Far-side activity index
- Line-of-sight magnetic field  maps
- Vector magnetic field maps
- Coronal magnetic field extrapolations
- Coronal and solar wind models
- Brightness images
- Context magnetograms

## HMI Science Analysis Plan

- Magnetic Shear

## HMI Key Instrument Requirements

- Full sun 1.5 arc-second diffraction limited image
- Tunable filter with a 76 mÅ FWHM and a 500 mÅ tunable range
- Wavelength selection stability and repeatability of 0.18 mÅ
- Mechanism operation cycles over 5 years
- 80 million moves for the hollow core motors
- 40 million moves for the shutters
- Image stabilization system correction to 0.1 arc-second
- Filter temperature stability to 0.01 °C/hour
- CCD camera readout time of less than 3.4 seconds
- High speed data output of 55 Mbps

## HMI Design Heritage

**The HMI design is based on the successful Michelson Doppler Imager instrument.**

## HMI Design Improves on MDI

- HMI common design features based on MDI:
- Front window designed to be the initial filter with widest bandpass.
- Simple two element refracting telescope.
- Image Stabilization System with a solar limb sensor and PZT driven tip-tilt mirror.
- Narrow band tunable filter consisting of a multi-element Lyot filter and two Michelson interferometers.
- Similar hollow core motors, filterwheel mechanisms and shutters.
- HMI refinements from MDI:
- The observing line is the Fe I 617.3 nm absorption line instead of  the Ni I 676.8 nm line. This observing line is used for both Doppler and magnetic measurements.
- Rotating waveplates are used for polarization selection instead of a set of polarizing optics in a filterwheel mechanism.
- An additional tunable filter element is included in order to provide the measurement dynamic range required by the SDO orbit.
- The CCD format will be 4096x4096 pixels instead of 1024x1024 pixels in order to meet the angular resolution requirements.
- Two CCD cameras are used in parallel in order to make both Doppler and vector magnetic field measurements at the required cadence.
- The is no image processor – all observable computation is performed on the ground.

## HMI Optical Layout

## HMI Optics Package Layout

## Current Optics Package – 3D view

## HMI Subsystems

- Optics Package Structure
- The optic package subsystem includes the optics package structure, optical components mounts and legs that attach the optics package to the spacecraft.
- Optics Subsystem
- Includes all the optical elements except the filters.
- Filter subsystem
- The filter subsystem includes the front window, blocking filter, Lyot filter and Michelson interferometers
- Provides the ability to select the wavelength to image
- Thermal Subsystem
- Controls the temperature of the optics package, the filter oven, CCDs, and the front window.
- Implements the decontamination heating of the CCD.
- Image Stabilization Subsystem
- Consists of active mirror, limb sensor, precision digital & analog control electronics
- Actively stabilizes the image reducing the effects of jitter
- Mechanisms Subsystem
- The mechanisms subsystem includes shutters, hollow-core motors, calibration/focus wheels, alignment mechanism, and the aperture door.
- CCD Camera Subsystem
- The CCD camera subsystem includes 4Kx4K CCDs and the camera electronics box(es).
- HMI Electronics Subsystem
- Provides conditioned power and operation of  all HMI subsystems as well as HMI C&DH hardware.
- Software Subsystem
- The software subsystem includes the C&DH spacecraft interface and control of HMI subsystems

## Filter Subsystem

- Central wavelength 6173Å Fe I line
- Reject 99% of solar heat load from the OP interior
- Total bandwidth 76 mÅ FWHM
- Tunable range 500 mÅ
- Wavelength selection stability and repeatability of 0.18 mÅ
- The required bandwidth obtained by cascading filters as follows
- Front window 50Å
- Blocker 8Å
- Lyot filter (5 element 1:2:4:8:16) 306 mÅ
- Wide Michelson 172 mÅ
- Narrow Michelson  86 mÅ
- Tuning range requires use of three co-tuned elements
- Narrowest Lyot element
- Wide Michelson
- Narrow Michelson

## Image Stabilization Subsystem

- Stability is 0.1 arc-sec over periods of 90 seconds (TBC)
- Range ± 14 arc-sec
- Frequency range 0 to 50 Hz
- Continuous operation for life of mission

## Mechanisms (1 of 2)

- Shutters
- Repeatability		100 us
- Exposure range	50 ms to 90 sec
- Knowledge		30 us
- Life (5 year)		40 M exposures
- Hollow core motors
- Move time (60 deg)	< 800 ms
- Repeatability		60 arc-sec
- Accuracy		10 arc-min
- Life (5 year)		80 M moves

## Mechanisms (2 of 2)

- Calibration / focus wheels
- Positions				5
- Move time (1 step)		800 ms
- Accuracy				TBD arc-min
- Repeatability			TBD arc-min
- Life (5 Years)			20 K moves
- Alignment system
- Movement range			± 200 arc-sec
- Step size				2 arc-sec
- Aperture door
- Robust fail open design

## CCD Camera Subsystem

- Format			4096 x 4096 pixels
- Pixel size		12 um
- Full well			> 125K electrons
- Readout noise		40 electrons
- Readout time		< 3.4 seconds
- Digitization		12 bits
- Dark current		10 –e/sec/pixel at -60 °C

## HMI Dataflow Concept

- } Pipeline

## HMI Assembly & Integration Flow

**Operations****&****Analysis**

- Calibrate filter

- Verify optics performance

- Assemble/alignLyot cells

- Calibrate Michelsons

- Test oven & controller

- Assemble/cal.Lyot filter

- Assemble/testfilter oven system

- Test mechanisms

- Fabricate Optics Package

- Integrate focal plane

- Calibrate focal plane

- Integrate electronics, software, & OP

- Assemble & align in optics package

- Fabricate optical elements

- CCD detector

- Camera electronics

- Fabricate ISS

- Fabricate electronics

- Telescope structure

- Lyot element fabrication

- Optics fabrication

- Entrance filter

- Michelsons
- fabrication

- Oven & controller fabrication

- Fabricate mechanisms

- Fabricate focal plane

- Assemble & align on optical bench

- Verify optics performance

- HMI functional test

- HMI environmental test

- HMI calibration

- Spacecraft I&T

- Launch & commissioning

- Integrate &align telescope

- Test & calibrate ISS

- Develop Software

## Solar Orbiter

## Solar Orbiter Firsts

- Explore the uncharted innermost regions of our solar system
- Study the sun from close-up (48 Rs or 0.22 AU)
- Fly by the sun and examine the solar surface and the space above from a nearly co-rotating vantage point
- Provide images of the Sun’s polar regions from heliographic latitudes as high as (31°) 35°

##  Orbit    Ecliptic Plane Trajectory (Cruise)

** ****Orbit****    ****Ecliptic Plane Trajectory (Cruise)**

**Earth departure**

**Subsequent Venus swing-by’s**

**First Venus swing-by**

**  ****Closer to the Sun**
**  ****Out of the ecliptic**

**Earth swing-by**

**  ****GAM**
**  ****SEP**

##   Orbit: Science Phase

**in ecliptic plane**

**perpendicular to ecliptic plane**

## Mission Phases

##      S/C Heliographic Latitude  

- Year

**Degree    (solar equator)**

**35°**

##       S/C latitude versus radial distance

- AU

**Degree    (solar equator)**

##     Solar Orbiter Trajectory

##     Solar Orbiter Trajectory

##        Angle between Sun, S/C and Earth

**Synergy with SDO ****(Space Weather)**

**Year**

**90°**

##       Near Co-rotation around Perihelion

**Solar rotation rate 14.18°/day at the equator  **

**Science phase: - 2.5 ****° /day**
**- 5.4 ****° /day**

##        Preliminary Spacecraft Design

- Mission lifetime:  4.6 years    (extended: 7.3 years)
- Launcher: Soyuz-Fregat from Kourou (1495 kg)
- Propulsion: Solar Electric
- Science data rate:  75 kbs-1 (240 Gb on-board memory)
- Observations:   30 days around each perihelion & high/low latitude passes
- Orbital period:  150 days
- Technology borrowed from BepiColombo

## Challenges

- Heat load: up to 34 kWm-2 (25 solar constants), variable
- Radiation environment affects:
- Detectors
- Electronics
- Optical coatings and filters
- Limited spacecraft resources: mass, power, telemetry

-   Develop low-resource instrumentation (“keep it simple”)
-   Target and initiate new technology developments
-   Study critical payload and spacecraft issues
**On going:  Payload Working Group, Science Definition Team, Industrial studies (ESTEC), Studies by instrument consortia....   **

##         Solar Orbiter Scientific Goals

- Determine the properties, dynamics and interactions of plasma, fields and particles in the near-Sun heliosphere
- Investigate the links between the solar surface, corona and inner heliosphere
- Explore, at all latitudes, the energetics, dynamics and fine-scale structure of the Sun’s magnetized atmosphere
- Probe the solar dynamo by observing the Sun’s high-latitude field, flows and seismic waves

## Close-up Observations

- Imaging and spectroscopy, due to proximity, with an order of magnitude improvement over past missions

**     ****SOHO/EIT                                     TRACE ****	****                      ****Solar Orbiter**
**  ****1850 km pixels                           350 km pixels                               ****70 km pixels**

## Polar Magnetic Fields

**Solar Orbiter will allow us to study the:**
** ****magnetic structure and evolution of the polar regions,**
** ****detailed flow patterns in the polar regions,**
** ****development of magnetic structures, using ****local-area helioseismology at high latitudes.**

**Model magnetogram of the simulated solar cycle. The sun viewed from a latitude of 30° north of the ecliptic (courtesy Schrijver)**** **

## Polar Rotation and Flows

- What are the rotation and flow patterns in the polar regions?

## The Sun’s Polar Regions and Equatorial Corona

- Coronal mass ejection longitudinal extent and global distribution

*Viewing from out of the ecliptic plane allows the Solar Orbiter to study*

*- CME longitudinal              spreads                                           *
*- CME directions                             *
*- the global distribution of CMEs**                                 *

## Baseline  Mission (SDT)

| Instrument | Mass
kg | Power
W | Rate
kbps |
| --- | --- | --- | --- |
| Plasma Package (SWA) | 15.5 | 11 | 14 |
| Fields Package (MAG +RPW + CRS) | 11 | 13 | 5.8 |
| Particles Package (incl. Neutrons,gammas & dust) | 15 | 15 | 4.5 |
| Visible Light Imager & Magnetograph (VIM) | 30 | 25 | 20 |
| EU Imager (3 telescopes incl. FSI) | 30 | 25 | 20 |
| EU Spectrometer | 25 | 25 | 17 |
| Spectrometer/Telescope Imaging X-rays (STIX) |  4 |  4 | 0.2 |
| Coronagraph (COR) | 10 | 10 |  7 |
| Total | 140.5 | 128 | 88.5 |

##       Solar Orbiter Status

- Following the SDT activities in 2003, Solar Orbiter is presently undergoing re-assessment in ESA:
- Payload Integration Study
- 	(performed in industry, January-June 2004)
- ESTEC Concurrent Design Facility (CDF) Study
- 	(Update to the CDF study in 1999, 4 sessions, March 2004)
- Two Parallel System-level Assessment Studies
- 	(performed in industry, April-December 2004).
- Current launch date:** March 2015**

##  Global Strategy – Missions and Goals

- Out of Sun-Earth line/multi-point observations [Earth-directed ejecta, CMEs]

- High latitude [polar processes and dynamo, 3-D star/CMEs]

- Close up/near co-rotation [linking Sun and inner heliosphere]

- Very-high resolution/Earth Orbit [fundamental processes]

- NASA STEREO [2006]

- ISAS Solar-B [2006], NASA SDO [2008]

- ESA Solar Orbiter

## Summary

- Target launch date: 2015
- Open to international collaboration
- Technological challenges
- Heat load (up to 34 kW/m2, and highly variable)
- Particle environment
- ...
- Rewards: exciting new “firsts”
- Exploration of unknown territory near the Sun
- First images of the solar poles
- Unprecedented high-resolution observations of the Sun
- Correlation of in-situ & remote-sensing measurements at 45 R from a co-rotational vantage point

## Solar Probe

- Primary Science Objective
- Understand the processes that heat the solar corona and produce the solar wind.
- Mission Profile
- Arrive at the Sun at polar trajectory perpendicular to Sun-Earth line
- Perihelion at 4 R at solar equator
- Distance over poles: 8 R
- Payload: *Mass: 19 kg, Power: 16 W*
- Remote Sensing Instruments
- Magnetograph/Helioseismograph
- XUV imager
- All-sky, 3-D coronagraph imager
- In-situ Instruments
- Vector magnetometer
- Solar wind ion composition and electron spectrometer
- Energetic particle composition spectrometer
- Plasma wave sensor
- Fast solar wind ion detector

## Solar Probe

## Solar Sentinels

- Set of notional missions to investigate the physics of the interplanetary medium that links solar processes to Earth’s environment
- Objectives
- Global characterization of the heliosphere
- Transit and evolution of geoeffective structures
- Connecting geoeffective structures to solar features/activity
- Location and mechanism of energetic particle release and acceleration

## Solar Sentinels

**Far Side****Sentinel**

**Inner Heliospheric **
**Sentinels**

**L1 Sentinel**

-  Far Side Sentinel    		   - 3-axis stabilized spacecraft
-  Inner Heliospheric Sentinels	   - 4 spinning s/c in 0.5-0.95 AU				      heliocentric orbits
-  L1 Sentinel			   - Spinning s/c in L1 Halo orbit

## Scientific Rational
SOHO (EIT, LASCO) and TRACE have provided dramatic images of solar events
Modeling and prediction remain a puzzle because 
The energy transfer processes are controversial 
The physical interpretations are poorly constrained by observations
The missing piece of the puzzle...
Mass motions within structures, which are not observable with current instruments

- SOHO (EIT, LASCO) and TRACE have provided dramatic images of solar events
- Modeling and prediction remain a puzzle because
- The energy transfer processes are controversial
- The physical interpretations are poorly constrained by observations
- The missing piece of the puzzle...
- Mass motions within structures, which are not observable with current instruments

**NEXUS provides measurements of mass motions within coronal structures.**

_**N**_**ormal-incidence **_**Ex**_**treme **_**U**_**ltraviolet **_**S**_**pectrograph (NEXUS)**

## NEXUS Perfomance

- Better instantaneous temperature coverage
- Simultaneous chromosphere, Transition Region, and Corona
- Better time resolution
- Larger effective area
- Better spatial resolution
- Equivalent to TRACE

**NEXUS Baseline**

**NEXUS Minimum**

**Solar-B/EIS**

**SOHO/CDS**

**SOHO/SUMER**

**No other planned or existing instrument will accomplish NEXUS science**

## NEXUS: Imaging Spectrograph

- Solar disk is imaged at the slit
- Most of image is rejected out front door
- Portion goes through entrance slit
- Emission lines are dispersed by grating and focused on ICCD detector

## NEXUS: Data Analysis – Spectra to Physics

**Wide slit provides 1’ x 1’ mini-images which allow coalignment on the ground**

**Spatially resolved line profiles are observed in narrow slit**

- 1/2 arcsec

- Laboratory Rest Wavelength

**Intensity **– Measures plasma density, same as image
**Doppler Shift** – Measures line-of-sight flow velocity
**Width** – Measures unresolved turbulence in the plasma

**NEXUS: Data Analysis – Spectra to Physics**

**Observed Emission Line**

**Resolved Components**

**Each emission line reproduces spectrograph aperture **

**Physical Parameters**

**Each spatially resolved element is analyzed to obtain both intensity and velocity information**

**Ground Co-Alignment**

**Line identification gives temperature**

- Doppler Shift

- Width

- Intensity

## NEXUS: Imaging Dynamics

## NEXUS Mission Implementation

**Orbit** - 575 km altitude, 97.79° inclination, Sun Synchronous Twilight Orbit

**Instrument**** - **A Single Extreme Ultraviolet Range Spectrograph

**Spacecraft **

- Derivative of C/NOFS and GLAST Spacecraft With Limited, Selective Redundancy
- Three-Axis Attitude Control
- Solar pointed based on Stellar & Sun Based (Boresight Telescope) Attitude Determination

**Mission Operations **

- Supports Continuous Operations
- Primary Ground Station at RAL
- Supporting Station & Early Operations Ground Stations at Poker Flat and Wallops

**Launch Vehicle - **Pegasus XL with HAPS
**Launch Site** - VAFB
**Launch Date** - April, 2008

**SPACE SEGMENT**

**LAUNCH SEGMENT**

**GROUND SEGMENT**

**Poker Flat & Wallops Alternate**
**Ground Stations**

**GSFC Science Operations Center**

**NEXUS Mission Implementation**

**NEXUS Observatory On-Orbit Configuration**

**GSFC Mission Operations Center**

**Rutherford Appleton Labs**
**Ground Station**

**Science & SOH Data**

**Commands**

**Science Plans**

**Raw Data Files**

**Level 0 Data**

**Level 1 Data  to NEXUS HQ Program Scientist**

##   Investigation of the Solar Interface by Transient Exploration (INSITE) 

- Science Objectives
- Transport, transformation, and dissipation of energy in the interfaceregion from solar surface to corona.
- How do matter and field interact in a region where they compete for dominance?
- Where are different types of energy generated and dissipated that lead to solar activity?
- How does matter enter and leave the outer solar atmosphere?
- Science Payload
- 30 cm UV telescope with spectrograph covering 1329-1409 Å and 1525-1565 Å at 40 mÅ with 6 cm2 effective area, and slit jaw imaging at 1600 Å, 1700 Å & white light, all at 0.33” resolution
- 60-600 times throughput of SOHO/SUMER
- 15 cm 2 channel EUV telescope for coronal imaging (171 Å and 133 Å) at 0.33” resolution
- Mission Description
- Sun-synchronous orbit for continuous observations
- Average data rat: 10 Gbyte/day
- Weight: 207 kg (84 kg instrument, 123 kg bus)

## INSITE

##           Reconnection and Mircroscale Probe (RAM)

- Science Objectives
- What are the mechanisms that lead to reconnection?
- What micro-scale instabilities lead to global effects?
- Where are the regions of particle acceleration?
- Where are the reconnection regions and what is their topology?
- Mission Description
- Continuous solar observations from geostationary orbit
- NASA STP-class mission
- Mission lifetime: 3 years (launch 2009+?)
- Measurements
- Ultra-high (0.02 arcsec/pixel) EUV coronal imaging
- High resolution (0.1 arcsec/pixel) EUV/UV spectroscopy
- X-ray imaging spectroscopy (1 arsec/pixel, 500 @ 1 keV, msec time resolution)
- Multi-wavelength EUV/UV intermediate scale imager (0.1 arcsec/pixel)

## Telemachus

- Science Objectives
- Reveal through helioseismology how convection and rotation couple and magnetic flux accumulates in the polar regions (solar dynamo)
- Acceleration of solar wind in polar regions and expulsion of plasma and magnetic fields
- Distribution of radio and x-ray emission from all solar longitudes
- Stream/stream plasma interactions
- Mission Description
- Ballistic trajectory with Jupiter gravity assist
- 8.4 yr cruise, 3 yr science
- 0.2 x 2.5 AU final orbit, period 1.5 yr
- 90o heliographic inclination
- Payload: 33 kg, 42 W, 8 kbps

## Solar Polar Imager

- Science Objectives
- Measure Sun’s polar magnetic field and refine solar dynamo models
- Measure meridional circulation and sub-surface jets
- Image global effects of CMEs and evolution of the full 3D corona
- Mission Description
- Solar sail trajectory (solar sail @ 10-14 g/m2, 100-141 m radius)
- 4-5 years flight time, 2 years ops
- Final orbit: 0.48 AU @ 60o inclination
- Payload: 34 kg, 24.5 W, 15.6 kbps
- Measurements
- Surface velocity for helioseismology
- Magnetic fields
- Corona and CMEs from over the poles
- In-situ particles and fields
- Solar irradiance in polar regions

## Magnetic Transition Region Probe

- Science Objectives
- 3D structure and dynamics of the magnetic transition region between the photosphere and upper chromosphere
- Resolve and measure the appearance, transport, and destruction of magnetic field on the fundamental intergranular scales in the photosphere
- Mission Description
- Geo-synch orbit
- 3 years in orbit
- 750 Mbit/s
- Measurements
- Visible/infrared maps/images of vector magnetic field with large FOV (> 100,000 km), high res (< 100 km), and high sensitivity (< 30 G, transverse)
- UV and EUV maps/images of chromosphere, transition region and coronal structures

## Particle Acceleration Solar Orbiter

- Science Objectives
- Understand particle acceleration mechanisms
- Nature of energy release and particle acceleration
- Flare vs. shock acceleration
- Mission Description
- Solar Sail Trajectory (solar sail @ 9g/m2, 87 m radius)
- Circular solar equatorial orbit at 0.169 AU (P = 25.4 days)
- 3 year transition to final orbit, 4-5 years in final orbit
- Spin-stabilized platform (500 kg, 80 kg for payload)
- Measurements
- High energy solar flare imager (< 1 arcsec)
- 1-100 MeV/nuc, resolve composition up to Fe
- Neutron spectrometer
- Gamma ray spectrometer for nuclear lines
- Solar wind and magnetic field instruments

## Solar Imaging Radio Array

- Science Objectives
- CME structure, propagation, and evolution from the Sun to 1 AU
- Apply solar radio burst images to mapping of solar wind density structures and magnetic field topology
- Enhance space weather prediction capabilities
- Image the low-frequency (<30 MHz) radio universe at high angular resolution
- Mission Description
- Microsat constellation of 10-16 identical spacecraft
- Quasi-spherical constellation with            < 100 km diameter
- Crossed dipole antennas and low frequency radio receivers
- Measurements
- Frequency range from 30 MHz to 30 kHz
- High spatial and temporal resolution

##    Sun, Heliosphere, Earth Constellation

- Science Objectives
- Provide long-term relevant information on the Earth, Sun and its interconnecting medium as a system
- Understand, monitor and track the Sun, Earth and Heliosphere as a dynamic and evolving system
- Provide timely reports and predictions on the status and possible major disturbances in the Earth-Sun system
- Mission Description
- Establish and operational constellation of sensor suite(s) that satisfies the mission objectives
- Deploy sufficient sensors (and replace over time) to measure the relevant data
- Implement data processing capability and information network to provide the required services
- Measurements
- Remote and in-situ sensing of the Sun from locations needed to provide data for proven predictive models

## Stellar Imager

- Science Objectives
- Explore surface magnetic fields throughout activity cycles on a substantial sample of stars like the  Sun to develop and test a predictive dynamo model for the Sun.
- Image the structure and differential rotation of stellar interiors by the asteroseismic technique of acoustic imaging (30 resolution elements @      1 min cadence)
- Mission Description
- 9 or more coordinated spacecraft in formation flying at L2
- Measurements
- UV images of stars with resolution better than 0.1 milli-arcsec
- At least 20 images within stellar rotation period to measure surface differential rotation and field evolution
- Revisit targets repeatedly during 3-6 months intervals over 5-10 years

## Summary

**Summary**

-  Solar Dynamics Obs. [2008] – NASA
-         Magnetic field evolution – subsurface to corona – high time res.

- STEREO [2006] – NASA
-         Out of Sun-Earth line, 3-D, CMEs

- Solar Probe / Sentinels – NASA ?
-             A closer look

- Solar-B [2006] – ISAS
-         High resolution magnetic field

- Solar Orbiter [2015] – ESA
-           Out of ecliptic, far-side, co-rotation, inner heliosphere

- RAM ? – NASA ?
-              corona, ultra high resolution