01 woods eve intro - lasp.colorado.edu

Introduction to EVE WorkshopOverview of EVE Instrument

Tom [email protected]

OutlineEVE Workshop Objectives / AgendaOverview of EVE Science PlanEVE Instrument Overview

EVE Instrument

Woods – EVE Introduction

NASA 36.240 Spectrum - April 14, 2008


Some Objectives for EVE WorkshopMarvel over rocket EVE measurement

April 14, 2008 launchWHI quiet Sun campaign

Reference spectrum for cycle minimumDEM and other solar modeling

Calm before the storm (data flood)Now is the time to…

Complete pre-flight calibration analysisPrepare data processing codePrepare models for EVE dataWrite instrument papers

Compare photoelectron models / resultsSolar EUV from TIMED SEE & modelsAirglow from TIMED GUVIFLIP, glow, & AURIC models


Agenda - 1


Agenda - 2


Agenda - 3


SDO Investigations:Helioseismic Magnetic Imager (HMI); PI: Phil Scherrer – Stanford Univ.;

Images the Sun’s helioseismic and magnetic fields to understand the Sun’s interior and magnetic activity.

Atmospheric Imaging Assembly (AIA) and Guide Telescopes (GT); PI: Alan Title – LMSAL;

Multiple simultaneous, high-resolution images of the corona over a wide range of temperatures.

Extreme ultraviolet Variability Experiment (EVE); PI: Tom Woods –LASP, Univ. of Colorado

Measures the solar extreme ultraviolet (EUV) irradiance to understand variations.

HMI

EVE

Instrument Module

S/C Bus & Prop. Modules

Solar Arrays

Antenna Booms

AIA SUITE

Solar Dynamics Observatory (SDO)

First Mission for NASA’s Living with a Star (LWS)–How the Sun’s magnetic field is generated and structured–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 the solar irradiance.


EVE Science Team

EVE Data Products and Research PlansEVE Data Products:

Near real-time space weather data product: solar EUV irradiance for NOAA SWPC operationsHigh quality solar EUV irradiances on 10-sec cadence and averaged over 1-day provided daily to EVE’s archive and FTP distribution center

EVE Models:Solar irradiance: NRLEUV, SIP, FISMGlobal thermosphere / ionosphere: CTIM, TDIM, GAIM

Space Weather Operations1-min cadence (10-sec)< 15-min latency

Research / Model Development10-sec cadence (0.25-sec)< 1-day latency


EVE Science Team

EVE Team: Data Products and Research PlansEVE Data Products:

Near real-time space weather data product: solar EUV irradiance for NOAA SWPC operationsHigh quality solar EUV irradiances on 10-sec cadence and averaged over 1-day provided daily to EVE’s archive and FTP distribution center


EVE ScientistsLASP / CUTom WoodsFrank EparvierPhil ChamberlinAndrew JonesRachel Hock

USCDarrell JudgeLeonid Didkovsky

SEC / NOAARodney Viereck

LL / MITGreg Berthiaume

SET Kent Tobiska

NRLJudith LeanJohn MariskaHarry Warren CIRES / CU

Tim Fuller-Rowell

USUJan Sojka

VirginiaTech Scott Bailey

EPO – CU/CIRESMark McCaffreySusan Buhr


Space Weather CommunitySDO Science Team

EVE Science Team

EVE integrated with other SDO and Sp Wx effortsEVE Data Products:

Near real-time space weather data product: solar EUV irradiance for NOAA SEC operationsHigh quality solar EUV irradiances on 10-sec cadence and averaged over 1-day provided daily to EVE’s archive and FTP distribution center


EVE and AIA (the full-disk imager):

Images identify solar sources of irradiance variability: improve irradiance models and predictions EVE results provide calibration for EUV images

EVE and HMI (the vector magnetograph):

Magnetograms identify relationship of magnetic flux transport and evolution with irradiance variabilityUse solar farside “imaging” and flux transport to improve irradiance predictions

Solar EUV Irradiance:

Improve and understand how and why solar EUV spectral irradiance varies on all time scalesImprove capability to predict (nowcast and forecast) variability

Geospace Impacts:Understand the response of geospace to solar EUV variability on all time scalesProvide improved and real-time solar drivers for atmospheric models


What information is missing for EUV irradiance?That is, what is limiting our advances now?1) Spectral information below 27 nm

Present measurements are only broad band below 27 nm (7-10 nm bands)Much of the flare energy is released below 30 nm, BUT we don’t know the spectral distribution to discern individual emission lines

* TSI Flare Energy

XUV (0-30 nm)Flare Energy25% disk center100% at limb

From Woods et al., JGR, 2006.


What information is missing for EUV irradiance?That is, what is limiting our advances now?1) Spectral information below 27 nm2) Lack spectral details of flare phases (e.g., precursor, impulsive phase, gradual

phase)Simultaneous measurement of all EUV wavelengths is required and only possible with array detectorsProgress has been made with TIMED SEE measurements (e.g. FISM model), BUT TIMED measurements only have 3% duty cycle and thus limited flare measurements

From Phil Chamberlin, FISM, PhD Dissertation, 2005.

Gradual Phase variability is larger than solar cycle for many emission lines

Impulsive Phase variability is very low above 170 nm and also below 30 nm


What information is missing for EUV irradiance?That is, what is limiting our advances now?1) Spectral information below 27 nm2) Lack spectral details of flare phases (e.g., precursor, impulsive phase,

gradual phase)3) How important are EUV flares (versus X-ray flares) for space weather?

X-ray flares are common (almost daily, ~1 large flare per month)EUV flares usually occur with X-ray increases BUT sometimes EUV flares are without X-ray flares and vice versa (from D. McMullin, SOHO SEM & GOES XRS)BUT we don’t have full coverage to know the spectral extent of these EUV flares

EUVX-Ray

EUV and X-ray Flares Tracking Each Other

EUVX-Ray

X-ray Flare But Reduced EUV Flare


What information is missing for EUV irradiance?That is, what is limiting our advances now?1) Spectral information below 27 nm2) Lack spectral details of flare phases (e.g., precursor, impulsive phase, gradual

phase)3) How important are EUV flares (versus X-ray flares) for space weather?4) Are there reliable precursors for forecasting EUV irradiance and flare events?

Concurrent solar EUV and magnetic field images with solar EUV spectral irradiance measurements from SDO at high cadence are expected to revolutionize our understanding of EUV radiation and especially flare events

EIT

284

Example from Judith Lean

Flux emerging on east limb can be used to predict daily EUV irradiance.

How does SDO EVE measure the EUV spectrum?Multiple EUV Grating Spectrograph (MEGS)

at 0.1 nm resolutionMEGS-A: 5-37 nmMEGS-B: 35-105 nm

at 1 nm resolutionMEGS-SAM: 0-7 nm

at 10 nm resolutionMEGS-Photometers: @ 122 nm

Ly-α Proxy for: H I emissions at 80-102 nm He I emissions at 45-58 nm

Δλ0.114710nm

EUV Spectrophotometer (ESP)at 4 nm resolution

17.5, 25.6, 30.4, 36 nmat 7 nm resolution

0-7 nm (zeroth order)In-flight calibrations from ESP and MEGS-P on daily basis and also annual calibration rocket flights


EVE Instrument Overview

SDO Spacecraft

AIAHMI

EVE MEGS – Multiple EUV Grating SpectrographMEGS-A : grazing incidence, cooled CCDMEGS-B : dual, normal incidence, cooled CCDMEGS-SAM : pinhole camera, MEGS-A CCDMEGS-P : Si photodiode in MEGS-B

ESP – EUV SpectroPhotometerTransmission grating, Si photodiodes, Quad-diode

EEB - EVE Electrical Box

Backup Slides on EVE Channels

Multiple EUV Grating Spectrograph (MEGS) Optical Overview

CCD B

CCD A

B Grating 1

CCD Electronics Radiator

SAM

B Grating 2

A grating

MEGS PElectrometers

Aperture Doors

Filter Mechanisms

MEGS B

MEGS A

λ Range A: 5-37 nm, B: 34-105 nm, SAM: 0.1-7 nm, P: 121.6 nm

Δλ Resolution A & B: 0.1 nm, SAM & P: 1 nm

Time Cadence A,B,SAM: 10 sec, P: 0.25 sec

Field of View ±2°

Power 22 W

Data 6.8 Mbps

MechanismsOne-shot Aperture

Door (3)

Five-position Filter Wheel (3)

Detectors1024 x 2048 CCDs

(2)

Si Photodiodes (2)


Solar Aspect Monitor (SAM) Solar Spectrum

SAM Image on MEGS A CCD

Entrance SlitFilterWheel

OpticalAxis CCD Detector

Door

MEGS A Light Rays

* Power, CCD, and detector are accounted for in the MEGS A budgets

SAM is a pinhole camera with photon-counting technique for X-rays:SPECTRA and IMAGES

λ Range 0.1 - 7 nmΔλ Resolution 0.01 - 1 nmTime Cadence

10 sec

Field of View ± 2°Aperture Door

One-shot

Filter Wheel 5 positionsCCD Detector *Average Power

*

Data *


MEGS A Overview

OpticalAxis

CCD Detector

Door

Entrance SlitFilterWheel

Solar Spectrum

CCD Image of Solar Spectrum

Slit 15-20 nm

Slit 217-37 nm

SAM images have 10 arc-sec pixels

λ Range 5 - 37 nmΔλ Resolution 0.1 nmTime Cadence 10 secField of View ±2°Aperture Door One-shotFilter Wheel 5 positionsCCD Detector 1024 x 2048Power 11 WData 3.4 Mbps


MEGS B Overview Solar Spectrum

OpticalAxis

CCD Detector

Door

Entrance Slit

FilterWheel

B Grating 2

Primary First Order

Higher Orders

Higher Orders

λ Range 34 - 105 nmΔλ Resolution 0.1 nmTime Cadence 10 secField of View ±2°Aperture Door One-shotFilter Wheel 5 positionsCCD Detector 1024 x 2048Power 11 WData 3.4 Mbps


MEGS P Overview Solar Spectrum

Image on MEGS P Detector

MEGS B Grating 1

121 nm Filter& Detector

MEGS B Filter Wheel

Dark Detector

* Behind MEGS B mechanisms

λ Range 121.6 nmΔλ Resolution 1 nmTime Cadence 0.25 secField of View ±2°Aperture Door *Filter Wheel *Si Photodiode 1 cm x 1 cmPower 0.2 WData 0.001 Mbps

EUV SpectroPhotometer (ESP) Optical Overviewλ Range 1st: 18.4, 25.5, 30.4, 35.5 nm

0th order: 0.1-7 nm

Δλ Resolution 1st: 4 nm 0th: 7 nm

Time Cadence 0.25 sec

Field of View ±2°

Power 1.9 W

Data 0.007 Mbps

Solar Spectrum

Filter WheelTransmission

GratingDetector Plane

Ti FilterDiode Electrometers

ApertureDoor

Filter WheelMechanismsOne-shot Aperture

Door (1)

Five-position Filter Wheel (1)

DetectorsSi Photodiodes (5)

Quad Si Photodiode (1 - 0th order)

USC’s ESP instrument is similar to SOHO SEM

01 woods eve intro - lasp.colorado.edu

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