1. UV Spectro-Coronagraphic Observations of Solar Energetic Particle Related Phenomena J.S. Newmark, J. Daniel Moses, J. Martin Laming, C.E. Rakowski, A.J. Tylka, D. G. Socker Naval Research Laboratory, Washington, DC USA Introduction One of the most difficult problems in space weather is the prediction of Solar Energetic Particles (SEPs). New theoretical models are providing information about the precise source region of the energetic particles. Instead of blasting outward from the flare itself, in the largest SEP events these particles apparently arise from a coronal seed population accelerated by a shock originating in the corona and propagating into interplanetary space. NRL has developed concepts for a new generation of instruments to provide new insights into energetic particle-producing Coronal Mass Ejections (CMEs) and the associated shocks as they traverse the corona and enter the solar wind. This understanding of SEP shocks is directly relevant for Space Weather prediction as they uniquely define the source regions for geo-effective events. Specifically, the empirical characterization of the coronal pre- shock/shock conditions and the ambient solar wind properties can be directly used as inputs for shock propagation and SEP acceleration models. Such observations on real events are required to provide constraints on a comprehensive predictive SEP model. These new EUV/UV spectro-coronagraphs will observe the non-thermal characteristics of energetic particle-producing CMEs traversing the corona and inner heliosphere. Particle acceleration at CME shock fronts is a leading candidate for the production of SEP events. These instruments will demonstrate that the site of SEP acceleration can be identified and measure critical parameters in pre- and post-shock coronal plasmas including suprathermal seed particle populations. When combined with an integrated theory and modeling program, these measurements will be used to significantly advance our fundamental understanding of energetic particle acceleration. Ultimately this understanding will be used to develop a predictive capability for the flux, energy spectrum, and composition of SEPs and uniquely obtain the observations required to provide the basis for an unprecedented breakthrough in the prediction of SEP events. The instruments will detect the generation of suprathermal particle populations above the threshold necessary for efficient acceleration by shocks associated with high speed CMEs by providing sufficient throughput to detect high energy tails in the profiles of H I, He II and O VI. The non-thermal component detected in the UV/EUV spectra will indicate the presence of a population of seed particles that can be further accelerated in SEP events. Solar Orbiter Coronal Spectrometer (SOCS): Unique Viewpoint Observing Platform DoD Space Test Program: < 1 Year orbital flight, largely developed from components used on the Sub-orbital platform. Objective: Establish the validity of a new diagnostic for the acceleration of the ion component of Solar Energetic Particles (SEP) events. The ion component of SEP events is almost entirely responsible for the ionizing radiation damage to men and machines in space, yet the current diagnostic observables (radio, x-ray and gamma ray) are based on the acceleration of the electron component. => Identify presence of seed particle population; Predict the energetic ion flux and spectrum injected into IPM => This diagnostic will provide the basis for the first operational physics-based prediction of the severity of the largest SEP events. Technique: Observe the non-thermal characteristics of UV spectra of energetic particle-producing Coronal Mass Ejections (CMEs) traversing the corona and inner heliosphere. Particle acceleration at CME shock fronts is the leading candidate for the production of Solar Energetic Particle (SEP) events. Description: UVSC is the next logical step in a highly successful line of Space Weather research that includes SOHO LASCO/EIT and STEREO SECCHI as science and technology heritage. UVSC is an externally occulted Ultra-Violet coronagraph coupled to a multislit stigmatic spectrograph. A single spherical variable line space (SVLS) grating gives high throughput and low scatter spectrometer. The external occulter is a linear baffle on an extendable (9m) boom. UV Coronal Imaging-Spectrograph for the Parameterization of Coronal SEP Sources: Small Orbital Pathfinder Solar Energetic Particles and Suprathermal Ions: Science Principle Scientific Goals: * Characterize the hypothesized coronal suprathermal seed population and its role in the production of SEPs. * Characterize the sources of SEPs and how they are accelerated to high energy. Provide a Space Weather predictive tool for the most geo-effective SEP events. => Direct Observations of the Suprathermal SEP Seed Particles and Acceleration of the SEPs by CME driven shocks. UV Coronal Imaging-Spectrograph for the Parameterization of Coronal SEP Sources: UVCIS Pathfinder: Suborbital Design UVCIS will detect for the first time the presence, quantity, location and energy of coronal non-thermal particles needed to produce SEPs. Studying these particles is of paramount importance for predicting the occurrence of SEP storms in interplanetary space. UVCIS will demonstrate the observations required to determine the relationship between Coronal Mass Ejections (CME) shock dynamics and SEP acceleration. Increase the understanding of Space Weather events by providing in-flight demonstration of the technology to detect SEP related suprathermal seed particles and the required CME observations to complete the SEP shock modeling UVCIS will facilitate future missions studying SEP related phenomena by providing a successful demonstration of the design approach and technologies for use in a longer orbital mission. Combines the approaches developed with the suborbital Helium Resonant Scattering in the Corona and Heliosphere (HERSCHEL, PI J.D. Moses) program and extended with the technology development Ultraviolet Spectro-Coronagraph (UVSC, PI J.D. Moses) program with the key external occulter design (linear baffle) used on the STEREO SECCHI Heliospheric Imagers (HI). OVI 1032/1037 Spectra with 3 simultaneous slits at 1.8, 2.4, and 3.0 R  The objectives of this investigation are to answer the three questions of the HELEX program: What are the origins of the solar wind? What are the sources and acceleration processes that generate solar energetic particles? How do coronal mass ejections initiate and evolve in the heliosphere? High-resolution spectral observations of three EUV/UV wavebands provide critical measurements of the physical and dynamical properties for two of the three main components of coronal and interplanetary plasma: H and, for the first time, He => Understand and predict the drivers of major storms in the heliosphere. First time spectrally resolved He II, Lyα emission in the lower corona, and provide sufficient throughput to detect high energy tails in the profiles of H I, He II and O VI due to suprathermal particles. Develop more accurate Space Weather prediction algorithms. Correlate CME parameters with SEP events to provide tools to predict SEP event occurrence and magnitude. Measure electron-proton temperature equilibration behind fast CME shocks (v > 1500-2000 km/s) from HeII304/OVI1037 (following Laming et al. 1996, ApJ, 472, 267). Is this quantity related to pre-shock cosmic rays/ seed particles? See poster by Rakowski et al. at SPD/AGU meeting next week, and Rakowski, Laming & Ghavamian 2008, to appear on astro-ph soon! Long Term Space Weather MIDEX Class Mission Current NRL SMEX proposal, Coronal Physics EXplorer (CPEX, PI. D Socker) provides a major step forward. 2006 Roadmap provides two appropriate MIDEX missions: NESCE, SEPM that will completely fulfill the science requirements. We propose a similar MIDEX class mission: Science Objectives: * Characterize the hypothesized coronal suprathermal seed population and its role in the production of SEPs. * Characterize the sources of SEPs and how they are accelerated to high energy. * Provide a Space Weather predictive tool for the most geo-effective SEP events. Associated RFAs: F2. Understand the plasma processes that accelerate and transport particles. H1. Understand the causes and subsequent evolution of solar activity that affects Earth’s space J2. Develop the capability to predict the origin and onset of solar activity and disturbances associated with potentially hazardous space weather events. Measurement Strategy: * Observe with externally occulted EUV/UV and WL coronagraphs the spatial distribution of temperature, outflow velocity (via Doppler dimming) and Line-of-sight Doppler velocity, intensity, and density of multiple ions and electrons in the corona from 1.5 to 6 Solar radii. * Provide high resolution EUV/UV spectral line profiles of ions with various charge to mass ratios including OVI, He II, H, simultaneously at multiple heights in the corona. Provide spectral profiles of the high energy tails of OVI, He II, and H due to suprathermal particles. Mission Implementation Description: * Atlas, 650 km Sun-synchronous (~98.6 degrees) orbit * 3-axis stabilized, Sun-pointing, Solar array powered *EUV/UV imaging multi-slit spectro-coronagraph * White light imaging coronagraph Multi-slit instantaneous EUV/UV Spectra 1.8 2.0 2.4 2.7 DoD Space Test Program Mission Parameters: Dedicated Spacecraft Apogee: 400 +400 -0 km (>400 km) Perigee: 400 +400 -0 km (>400 km) Inclination: 98 +/- 1 deg Physical Data: 0.452 m 3, 35 kg, nominal 45 W Telemetry Volume: 2Gbits/day Volume = 150 cm L x 45 cm W x 67 cm H –Electronics Box (Included in total volume above): 23 cm L x 23 cm W x 13 cm H Why Required? Episodic Solar-Driven Disruption of Space Environment Geo-magnetic Storms: Solar Driver Understood - Geo-magnetic Storms: Solar Driver Understood - Addressed via CME paradigm established by NRL instruments: SOHO LASCO & EIT (Follow-on to STP P-78 SOLWIND) and STEREO SECCHI (Incorporating STP CMEWS) Solar Energetic Particles (SEP): Solar Driver Mystery - Solar Energetic Particles (SEP): Solar Driver Mystery - Outstanding problem lacking consensus on cause(s) of event to event variability of intensity, composition, and energy spectrum (i.e. severity). No direct observations at particle production and acceleration site have been made to address recent theories No direct observations at particle production and acceleration site have been made to address recent theories Basis of New Perspective on SEP: Prediction of Spectral and Compositional Variability: Several lines of evidence suggest that quasi-perp shocks may be particularly important in generating high-energy SEPs (Giacalone 2005; Tylka et al. 2005; Tylka & Lee 2006) and that particle acceleration at a quasi-perp shock is more effective in the presence of a suprathermal seed population (Jokipii 1987; Webb et al. 1995; Zank et al. 2004). Seed Particles from Preceding CMEs: SEP intensities correlate positively with CME speed, but with large scatter. What causes this scatter? Larger intensities occur when another CME has erupted from the same active regions <24 hours earlier. Preceding CMEs typically have speeds >700 km/s: fast enough to drive coronal shocks that would produce suprathermals. >10 MeV Proton Intensity vs. CME Speed With Preceding CME Without Preceding CME Gopalswamy et al. JGR 109, A12105 [2004] Several lines of evidence indicate that a pre-existing suprathermal seed population may be a critical driver behind the variability in SEP events. The effectiveness of shock acceleration is most likely enhanced by the availability of seed particles that have been pre-accelerated to a certain injection energy. Mason et al. 2005 shows a survey at 1 AU of variation in the intensity of suprathermal Fe ions, compared to an analogous survey of the bulk solar wind. The bulk solar-wind density varies by only a factor of ten, the suprathermal intensities span three orders of magnitude, the same magnitude as the scatter in SEP intensity variations. Of course, these suprathermals were observed at 1 AU From studies of traveling interplanetary shocks at 1AU estimates are that the SEP seed population must correspond to ~0.2% of local solar wind density => detect an SEP seed particle population in the pre-shock corona through the extended Doppler wings it would add to an emission line profile. UVCIS Multislit spatial position. The disk image will be blocked by an external occulter UVSC Pathfinder Configurations and Major Components Example OVI multislit (only 2 for clarity) data for visualization purposes CPEX Suprathermal seed particles as a key to large SEP events. Instrument technology based on high resolution, high throughput, low straylight, simultaneous multi-slit EUV/UV coronal spectroscopy.