Using non-linear force free field (NLFFF) extrapolation, 3D magnetic fields were modeled from the 12-min cadence Solar Dynamics Observatory Helioseismic and Magnetic Imager (HMI) photospheric vector magnetograms, spanning a time period of 1 hour before through 1 hour after the start of 18 X-class and 12 M-class solar flares. Several magnetic field parameters were calculated from the modeled fields directly, as well as from the power spectrum of surface maps generated by summing the fields along the vertical axis, for two different regions: areas with photospheric |Bz|≥ 300 G (active region—AR) and areas above the photosphere with the magnitude of the non-potential field (BNP) greater than three standard deviations above |BNP|̄ of the AR field and either the unsigned twist number |Tw| ≥ 1 turn or the shear angle Ψ ≥ 80° (non-potential region—NPR). Superposed epoch (SPE) plots of the magnetic field parameters were analyzed to investigate the evolution of the 3D solar field during the solar flare events and discern consistent trends across all solar flare events in the dataset, as well as across subsets of flare events categorized by their magnetic and sunspot classifications. The relationship between different flare properties and the magnetic field parameters was quantitatively described by the Spearman ranking correlation coefficient, rs. The parameters that showed the most consistent and discernable trends among the flare events, particularly for the hour leading up to the eruption, were the total unsigned flux ϕ), free magnetic energy (EFree), total unsigned magnetic twist (τTot), and total unsigned free magnetic twist (ρTot). Strong (|rs| ∈ [0.6, 0.8)) to very strong (|rs| ∈ [0.8, 1.0]) correlations were found between the magnetic field parameters and the following flare properties: peak X-ray flux, duration, rise time, decay time, impulsiveness, and integrated flux; the strongest correlation coefficient calculated for each flare property was 0.62, 0.85, 0.73, 0.82, −0.81, and 0.82, respectively.

With growing interest from the aviation and satellite industries, and for NASA's upcoming Artemis lunar missions, the need for improved scientific understanding and accurate forecasting of solar energetic particle events has never been stronger.In this paper we discuss the observational, validation and model transition support required to achieve these goals.Well-calibrated, high-quality energetic electron, proton, and ion measurements are essential.Expansions to the fields of view offered by current X-ray, extreme ultraviolet and coronagraph instruments, to obtain increased coverage of the solar corona and heliosphere, from vantage points off the Sun-Earth line, are desired for model input.New observations of suprathermal particles are needed to characterize seed particle distributions and low latency space-based observations of solar radio emissions are also desired.Together, this observational suite should offer high cadence, low latency, reliable and accurate space weather data streams.SEP models are a critical part of both understanding and predicting SEP radiation hazards.Consistent, extensive and quantitative validation is required to assess scientific understanding of SEP sources and pave the way for models transitioning to real-time forecast operations.Model performance and skill should be compared to observations and to current operational forecasting baselines.Finally, resources are required to support the significant effort of transitioning mature models into forecast operations.Visualization of CME and SEPs.

The current operational dimension available for space weather analysis and operations is not suitable for deep space exploration.As NASA plans for missions beyond the Low Earth Orbit (LEO), new advancements in modeling, observations, and communications are needed to establish a suitable monitoring and protection environment for the missions and the crew.The initial step is to establish multiple observational points that will improve the current analysis/modeling capabilities and extend them to deep space exploration missions.We summarize the value of multiple observational points, outline the current gaps (with examples) in providing operational space weather support for deep space exploration, and propose ideas for missions and international collaborations that will address these existing gaps.These proposed missions and collaborations will be essential to ensure a successful future for deep space exploration.

The coronal magnetic field over NOAA Active Region 11,429 during a X5.4 solar flare on 7 March 2012 is modeled using optimization based Non-Linear Force-Free Field extrapolation. Specifically, 3D magnetic fields were modeled for 11 timesteps using the 12-min cadence Solar Dynamics Observatory (SDO) Helioseismic and Magnetic Imager photospheric vector magnetic field data, spanning a time period of 1 hour before through 1 hour after the start of the flare. Using the modeled coronal magnetic field data, seven different magnetic field parameters were calculated for 3 separate regions: areas with surface | B z |≥ 300 G, areas of flare brightening seen in SDO Atmospheric Imaging Assembly imagery, and areas with surface | B | ≥ 1000 G and high twist. Time series of the magnetic field parameters were analyzed to investigate the evolution of the coronal field during the solar flare event and discern pre-eruptive signatures. The data shows that areas with | B | ≥ 1000 G and | T w |≥ 1.5 align well with areas of initial flare brightening during the pre-flare phase and at the beginning of the eruptive phase of the flare, suggesting that measurements of the photospheric magnetic field strength and twist can be used to predict the flare location within an active region if triggered. Additionally, the evolution of seven investigated magnetic field parameters indicated a destabilizing magnetic field structure that could likely erupt.

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Forecasting of solar flares remains a challenge due to the limited understanding of the triggering mechanisms associated with magnetic reconnection, the primary physical phenomenon connected to these events. Studies have indicated that changes to the photospheric magnetic fields associated with magnetic reconnection – particularly in relation to the field helicity – occur during solar flare events. This study utilized data from the Solar Dynamics Observatory (SDO) Helioseismic and Magnetic Imager (HMI) and SpaceWeather HMI Active Region Patches (SHARPs) to analyze full vector-field component data of the photospheric magnetic field during solar flare events within a near decade long HMI dataset. Analysis of the data was used to identify and compare the trends of differing flare classes for varying time intervals leading up to an event, as well as the trends of flares that occur with and without a precursor flare, in order to discern signatures of the physical mechanisms involved. The data suggests that active regions (AR) that produce flares with precursors are continuing to evolve and appreciably more complex than those that produce a flare without a precursor. Additionally, precursor flares were found to enhance the shear across an AR, helping set up the conditions necessary for a larger solar flare to occur. Ultimately none of the SHARP parameters showed a distinct signature of magnetic reconnection.

Solar flare forecasting is limited by the current understanding of mechanisms that govern magnetic reconnection, the main physical phenomenon associated with these events. As a result, forecasting relies mainly on climatological correlations to historical events rather than the underlying physics principles. Solar physics models place the neutral point of the reconnection event in the solar corona. Correspondingly, studies of photospheric magnetic fields indicate changes during solar flares—particularly in relation to the field helicity—on the solar surface as a result of the associated magnetic reconnection. This study utilizes data from the Solar Dynamics Observatory (SDO) Helioseismic and Magnetic Imager (HMI) and SpaceWeather HMI Active Region Patches (SHARPs) to analyze full vector-field component data of the photospheric magnetic field during solar flares within a large HMI dataset (May 2010 through September 2019). This analysis is then used to identify and compare trends in the different categories of flare strengths and determine indications of the physical phenomena taking place.

We use the Baranger model to compute collisional broadening and shift rates for theD(1)andD(2)spectral lines ofM+ Ng, whereM= K, Rb, Cs and Ng = He, Ne, Ar. Scattering matrix elements are calculated using the channel packet method, and non-adiabatic wavepacket dynamics are determined using the split-operator method together with a unitary transformation between adiabatic and diabatic representations. Scattering phase shift differences are weighted thermally and are integrated over temperatures ranging from 100 K to 800 K. We find that predicted broadening rates compare well with experiment, but shift rates are predicted poorly by this model because they are extremely sensitive to the near-asymptotic behavior of the potential energy surfaces.

The Drake equation is a calculation providing an upper bound on the likely number of intelligent species in our galaxy. In order to reconcile a potentially high occurrence of intelligent extraterrestrial species with the current non-observation of them, we frequently resort to some Great Filter which represents some inevitable, cataclysmic fate (such as nuclear war, pandemic, or asteroid impact) that tends to await enough worlds to negate the expectation that the galaxy ought to be teeming with intelligent life. This paper is intended to examine one potential Great Filter for electronic-based civilizations, the impact of a Carrington-class coronal mass ejection (CME) from the Sun. Carrington-class CMEs are classified as "once in a century" events caused by our Sun; this appears to place a time limit, following the development of a civilization dependent on electronic devices, either for hardening electronics against the geomagnetically induced currents that result from CMEs or for beginning interplanetary colonization.

The elemental composition of heavy ions (with atomic number Z > 2) (hi-Z) in large gradual E > 10 MeV nuc SEP events has been extensively studied in the 2-15 MeV nuc(-1) range to determine the acceleration processes and transport properties of SEPs. These studies invariably are based on abundances relative to those of a single element such as C or O and often neglect H and He, the elements of primary interest for space weather. The total radiation of an SEP event is determined not only by the H and He properties but also by those of hi-Z ions whose abundances and variations relative to H from one event to another are unknown. We report a study to determine those variations in a group of 15 large SEP events over the period 2000 to 2015. Five hi-Z ions (He, C, O, Mg, & Fe) were selected to determine variations of their fluences relative to those of H in the 13.5-50.7 MeV nuc(-1) energy range for each SEP event. Our average hi-Z abundance ratios slightly exceed those reported by [1] at lower energies, with the Fe event abundances showing the largest standard deviation of an order of magnitude. The event abundances were weakly correlated with H fluences and strongly correlated with speeds Vcme of associated coronal mass ejections (CMEs). These correlations may be evidence of streaming limits in the shock regions of H in the largest events.

Diode-pumped alkali metal vapor lasers (DPAL) offer significant promise for high average power. The DPAL system has high gain and will high output coupling and an unstable resonator to achieve excellent beam quality. We analyze the Rb-He system using average equations for the pump, laser and populations, including amplified spontaneous emission. We extend the formulation to include flow and temperature release and study its effects on the laser efficiency and beam quality. The design and analysis of the DPAL resonator and the influence of spatial variations in gain medium on far field beam quality are developed. A systematic study of the influence of gain medium aberrations, flow geometry, and resonator design on far field beam quality is reported. The relative advantages of longitudinal and transverse flow geometries to beam quality are evaluated. Finally, coupling of the pump and laser radiation fields is dramatic in the DPAL system. The standard approaches to merging CFD analysis of the gain medium with wave optics resonator simulations will require new techniques.

The performance of a 100 kW Rb-He diode pumped alkali laser system is predicted, including power scaling, optical efficiency, and beam quality. A transverse flow geometry with longitudinal diode pumping produces a nonlinear temperature profile in the flow direction, with temperature increasing by 124 K for a 0.5 m/s flow rate and a 30 kW/cm(2) pump intensity. The optical-to-optical efficiency is 70%, and the tilt-corrected Strehl is 0.545 for this slow flow, 45 ms residence time design. By increasing the flow speed to 15 m/s (1.5 ms residence time), the efficiency is improved to 82%, and the laminar flow beam quality is near the diffraction limit, Strehl > 0.99. Beam quality is adversely affected at higher helium pressure for the slow flow conditions.

The high gain Diode Pumped Alkali Laser (DPAL) system will require an unstable resonator with high Fresnel number and high output coupling to achieve excellent beam quality. Coupling of the diode pump and laser radiation fields is dramatic in the DPAL system. Merging flow field analysis of the gain medium with wave optics resonator simulations requires new techniques. We develop a wave-optics simulation of confocal, positive branch unstable resonators for the DPAL gain media to assess the limitations on far field beam quality. The design and analysis of the DPAL resonator and the influence of spatial variations in gain medium on far field beam quality are developed. The relative advantages of longitudinal and transverse flow geometries to beam quality are evaluated. A systematic study of the influence of gain medium aberrations, flow geometry, magnification, and resonator design on far field beam quality is reported.