F1B: Determine the Dominant Processes of Particle Acceleration Phase , Open the Frontier UV Spectroscopic determin- ation of pre/post-shock density, speed, compression; ion/ electron velocity distributions, charge states, abundances; Alfven speed, magnetic field, reconnection rates in CME shocks, flares, current sheets Enabling Capabilities & Measurements Implementation Phase 1: Required Understanding Shock acceleration processes Role of magnetic field topology Waves, turbulence & intermittent processes Coherent electric field acceleration Output Energy Spectrum and Composition Primary acceleration sites: - Coronal Mass Ejection Shocks - Solar flares, Current Sheets - Bow shocks, Radiation Belts - Magnetotails, Auroral Zones - Termination Shock ACE, SOHO, Wind, RHESSI, Cluster, IMAGE, Polar, FAST, TIMED, Voyager Current missions for particle acceleration Integrated Empirical Theory/Modeling Program To guide the evolution of physics based predictive theory Role of seed particle population STEREO, Solar-B For acceleration at CME/flare sites Stochastic acceleration processes Thermal plasma (solar wind) acceleration RBSP In-situ observation of acceleration processes, geospace sources of energetic particles Inner Heliospheric Sentinels Characterize SEP coronal source regions and emissions Multi-point In-situ measurements of density, temperature, velocity, energy spectrum, and charge state of particles; and electric/magnetic fields at coronal & heliospheric shocks Multi-point in-situ determinations of mag- netospheric energetic particles & fields at micro/meso-scales Visible light Coronagraph/ Polarimeter for electron density evolution and flow speeds Near-Sun measurements of neutrons, hard X-rays & gamma rays Neutral Energetic Ion Imaging of Termination Shock THEMIS, IBEX Explorer Missions for particle acceleration at I/F Existing Assets Explorer ProgramContributing SDO For acceleration at CME/flare sites IT-Imager Role of ionospheric conductivity for auroral acceleration STP ProgramEnablingLWS ProgramContributingLWS ProgramEnabling NESCE [Near-Earth Solar Coronal Explorer] Characterize SEP coronal source regions & emissions Potential ExplorerEnabling

H2A: Identify Precursors of Important Solar Disturbances Targeted Outcome: Phase , Opening the Frontier Enabling Capabilities & Measurements Implementation Phase 2: Targeted Understanding Coronal vector magnetic field evolution and subsurface field evolution UV Spectroscopic determination of Pre/Post-shock density, speed, compression; ion/electron velocity distributions, charge states, abundances; Alfven speed, magnetic field, reconnection rates in CME shocks, flares, current sheets Visible light Coronagraph/ Polarimeter for electron density structure and evolution CME magnetic field evolution behind the disk Near-Sun in situ measurements of charged particle distribution, comp- osition, waves & fields; neutrons, hard X-rays & gamma rays On-Disk UV/EUV Spectrographic imaging for flow velocities, energy release signatures; Disk Magnetograph for magnetic field topology and evolution Buildup of energy & helicity in coronal magnetic fields CME magnetic field orientation Relationship between eruptive filaments, active regions, CMEs, and SEPs Evolution of global solar magnetic field Relationship between CME shocks, flare/ CME current sheets and Solar Energetic Particles (SEPs) Relationship between global field and solar disturbances SDO for global magnetic field and active region measurements Solar Probe for near-Sun in situ observations SIRA to characterize CME shocks SEPP to fully characterize coronal sources of SEPs, CME shocks and current sheets DOPPLER to identify disk signatures of CME, flare, SEP initiation RAM to identify disk signatures of CME, flare, SEP initiation SHIELDS for tracking disk features behind the limb Radio burst measurements of near-Sun CME shocks Existing Assets Solar Orbiter for near-Sun in situ observations Enabling Flagship Mission Enabling LWS Program Enabling STP Program Contributing STP Program Contributing LWS Program Contributing Partnership

Near-Sun in situ measurements of charged particle distribution, composition, waves & fields; neutrons, hard X-rays & gamma rays Enabling Capabilities & Measurements Implementation Phase 2: Required Understanding Particle acceleration mechanisms in CME shocks and CME/flare current sheets Recognition of precursors of large CMEs, flares and SEP events responsible for major space weather disturbances SEPP to fully characterize coronal sources of SEPs, CME shocks and current sheets Solar Probe for in situ sampling of inner heliosphere Doppler to identify disk signatures of CME, flare, and SEP initiation Relationship between CME evolution and pre-existing solar wind conditions On-Disk UV/EUV Spectrographic imaging for flow velocities, energy release signatures; Disk Magnetograph for magnetic field topology and evolution UV Spectroscopic determin- ation of Pre/Post-shock density, speed, compression; ion/ electron velocity distributions, charge states, abundances; Alfven speed, magnetic field, reconnection rates in CME shocks, flares, current sheets Integrated empirical Theory/Modeling Program To guide the evolution of physics based predictive theory Visible light Coronagraph/ Polarimeter for electron density evolution and flow speeds Acceleration mechanisms and sources of the fast and slow solar wind Relationship between magnetic flux emergence & transport and the solar wind Link between magnetic field and solar wind at all latitudes High latitude observations of fields & particles SPI or Telemachus To characterize high latitude source regions J2A: Characterize the Near-Sun Source Region of the Space Environment Phase , Safeguard the Outward Journey Solar Orbiter for in situ sampling of inner heliosphere STEREO, SOLAR-B, SDO, SENTINELS STP and LWS missions from previous phases Assumed Phase 1 Assets Enabling Flagship Mission Contributing STP Program Contributing Partnership Enabling LWS Program