Revision History

Revision summaries for HELIOS are shown below:

• Version 10.1.0
• Version 10.0.0
• Version 9.1.0
• Version 9.0.1
• Version 9.0.0
• Versions earlier than 9.0.0

Next

Version 10.1.0

• Updates related to fusion burn physics:
  • Implemented algorithm for reducing the amount of available fusion fuel for burning plasma simulations.
  • Improved cross-sections for p+B11 reactions (based on Alessandro Tentori and Fabio Belloni 2023 Nucl. Fusion 63 086001).
  • Implemented scaling parameter for fusion rates.

  

• Multi-threaded implementation of particle transport.
• Improved algorithm for integrating particle trajectories within a zone and for computing deposited energy.
• Particle Beam kinetic energy (KE) can now be entered as a distribution, with multiple options for its input.

  

  The distribution option (e.g. Gaussian) appears in the first combo-box. For each distribution option (except Tabulated), the distribution is defined by one or more parameters. The parameter being specified appears in the second combo-box. Each parameter can be either time-independent or time-dependent.

  Normalization: the distributions only define the shape. When running the simulation, Helios will normalize the distributions such that the integral of the distribution, between the Binning Min. and Max. Energy, equals the Power at that time, which is defined in the Particle Beam Power section of the page. Note that the times do not need to match. Linear interpolation will be done in the case where time values do not match.

  Additionally, if there are hydro times which are before the lowest input time, the value at the lowest input time will be used. Similar treatment will be done for hydro times beyond the highest input time.

  Input options:

  • Mono-energetic:

    All particles have the same KE, thus "Energy" is the only entry in the combo-box.

  • Tabulated:
    This option uses a multi-column table for input for KE distributions. The first cell should not be edited--it is the title for the first column (energies). The remaining entries of the first row are time values (s). If your KE distribution is constant in time, you can leave this as having just one time column. Each remaining cell is then the dN/dE value for that energy and time. If the distribution is time-dependent, add an additional column (Edit > Add Column), and put its time value in the first cell of the column.

    Here is an example of a table of distributions for two times:

    

    The Table File option can be used by browsing for a text file with the following format. This would enter the same values as the table above:

    [table format=1]: Tabulated Particle beam KE:
    # table rows = 4
    # table cols = 3
    Energy [MeV]
    1.00000e-02 1.00000e-01 1.00000e+00 1.00000e+01
    1e-9
    1.00000e+10 1.50000e+10 2.30000e+10 3.60000e+10
    2e-9
    3.00000e+10 3.90000e+10 5.10000e+10 7.70000e+10

  • Maxwellian:

    The distribution will be a Maxwell-Boltzmann given by temperature "T" in MeV, i.e. the mean KE will also be "T" in MeV. Thus "T" is the only entry in the combo-box.

  • Power Law:

    The distribution will be E^-k where E is the KE, and k is dimensionless. Thus "k" is the only entry in the combo-box.

  • Gaussian:

    The distribution will be Gaussian with central KE given by "E0" and standard deviation"sigma". The combo-box thus has an entry for both "E0" and "sigma".

  Binning:

  The min. and max. energies define the range of the distribution, and should thus likely be chosen to contain the significant part of the distribution . E.g., E0-5*sigma to E0+5*sigma for a Gaussian, or 0.1*T to 10*T for a Maxwellian. For Tabular input, the min.-max. should generally match the table range, unless only part of the table is desired. Outside this binning range, the beam power will be zero.

  As noted above, the binning min. and max. energies also define the integration region for normalizing the energy distribution to the particle beam power.

  The number of particles created per time step will be the number of bins times the number of particles per bin. It is recommended to use 25 - 100 total particles. The number of particles created with energy distributions will be a factor of n_bins*np_per_bin more than in the mono-energetic beam.

• Added functionality to control continuum lowering models for CR calculations (Atomic Processes -> Advanced -> Dense plasma ) and to include dense plasma shifts. FAC CL option and dense plasma shifts require *.es atomic data files. The data will be distributed to all Helios-CR users.

Version 10.0.0

• Added option to specify the radiation sink in terms of leakage area A(t). The radiation energy lost by the system in a time step n is defined as A(t)cUⁿ⁺¹Δt/4, where U is the radiation energy density.
• Added support for large SESAME tables with up to 1 million words.
• Added initial support for SESAME ASCII2 format.
• Several significant changes in physics modules that affect CR simulations have been implemented. For more information on the models please refer to an appendix in the documentation titled "Physics Models Improvements April 2024"
• Photon energy grid refinement for both photo-absorption and spectral modeling.
• Continuum lowering model avoids destroying transitions just below the ionization threshold.
• Including more line wings in bound-bound emissivities.
• Extrapolation of photo-ionization cross sections below depressed ionization potential.
• Automatic adjustment of time steps for non-local time dependent population solver.
• Bug fixes:
  • For automatic zoning, fixed inconsistencies in determining masses/zone widths at the material interfaces.
  • Fixed energy conservation issues for simulations with the radiation sink.
  • Simulations with the radiation sink are now thread-safe.
• HydroPLOT:
  • Bug fixes:
    • Previously, when plotting Incident Flux or Incident Radiation Drive Temperature (Time tab, under Fluxes, for a given boundary), only the inner boundary (Rmin) values would be plotted, even when choosing the outer boundary. This has been fixed. (This was a problem only for plotting, not for Helios itself.)
• EOS and Opacity Viewer
  • Added support for large SESAME tables with up to 1 million words.
  • Added initial support for SESAME ASCII2 format.

Version 9.1.0

• Added ability to specify initial conditions for radiation temperature separately.





• Implemented improvements in opacity re-binning algorithm. Modest changes in simulations that use coarse radiation group structure can be expected.
• Updates were made to better support graphics on high-resolution monitors.
• Built with Qt 6.2.10.
• Distribution includes new set of default PROPACEOS tables (v. 6.0.0).
• Added batch command-line option (-n <int>) to specify the maximum number of threads for the simulation. This option overrides the default value in Preferences.
• For Helios-CR:
  • Improved continuum lowering model where the electron density and the amount of IPD are determined self consistently with a combination of iteration and bisection techniques was implemented. This model can significantly affect ionization balance, especially for low temperature plasma. More details on the model can be found in the Appendix of the main documentation.
  • Improved consistency in modeling IPD for mixtures of elements.
  • Improved models for ion contribution for Stark broadening. Previously, the effect of ion contribution could have been significantly overestimated at lower densities.
  • Added support for new distribution of FAC atomic data (v. 1.5.0U).
  • Improved algorithms for photon energy mesh in photo-ionization rate calculations.
  • Options were added to Preferences to control iterative continuum lowering.

  

• Bug fixes:
  • Fixed rare potential crashes when using NLTE EOS with Helios-CR.
• HydroPLOT:
  • Built with Qt 6.2.10.
  • Bug fixes:
• EOS and Opacity Viewer
  • Built with Qt 6.2.10.
  • Ionization Fraction results can now be plotted, by selecting the Display | Ion Fractions Data menu item. They can be plotted vs. Ionization Stage (giving an ionization distribution), or for a given stage vs. temperature or density. The interface uses a new plot window:

  

Version 9.0.1

• Bug fixes:
  • On some platforms, graphical progress monitor could fail to update. This has been fixed.

Version 9.0.0

• This version of HELIOS is built with a new version of Qt - a cross-platform framework for creating user interfaces and graphics. This is a major upgrade to the long-term support version of Qt 6.2.6. It was required to ensure stable operation of Prism software on the most recent Windows, Mac, and Linux operating systems.
• Added option to perform CR calculations with NLTE EOS. This feature is based on the formalism described in: H.A. Scott, “Collisional-Radiative Modeling for Radiation Hydrodynamics Codes”, Chapter 4 in Modern Methods in "Collisional-Radiative Modeling of Plasmas”, Springer Series on Atomic, Optical, and Plasma Physics, Vol 90 (2016). Utilization of the model may increase simulation time by a factor of two. Also, proper atomic models need to be used in order to obtain physically meaningful results. This is a new feature; user feedback will be appreciated.

  

• For Helios-CR users: New Stark broadening models were implemented based on the semi-empirical approach detailed in Gu and Beirsdorfer (Phys. Rev. A, 101, 032501). Users can control whether to use the old or the new Stark broadening model in preferences for each application. The default option is to use the new model. For more information on the models please refer to an appendix in the documentation titled "Stark Broadening Models in Prism Codes".

  

• Bug fixes:
  • For CR zones, Ionization Fractions were sometimes not written correctly to the Exodus file when more than one material was used.
  • For non-CR zones, Ionization Fractions were sometimes not written correctly to the Exodus file when three or more materials were used.
  • Apply floor for temperature derivative of pressures that is consistent with existing floor for temperature derivatives of specific energies.
  • Fix for potential issues with simulations that use SESAME tables with different temperature/density grids for ions (303 table) and electrons (304 table)
  • In some calculations that resulted in frequent updates of the graphical progress monitor, there was a potential for increased simulation time. Algorithms for limiting graphical output were implemented to address this issue.
• HydroPLOT:
  • HydroPLOT has also been updated to use Qt 6.2.6.
  • Reading in HydroPLOT workspaces previously saved using HydroPLOT versions 8.0.0 and earlier is not supported. If utilizing those workspaces is necessary, it is recommended that the relevant earlier version of HydroPLOT be used.
  • Bug fixes:
    • Plotting "Ionization Fractions" (and "Kinetic Energy per Ion" for CR zones) has been fixed.
    • Applying spectral resolution is now supported for HELIOS exo-formatted output files.
    • If one or more materials had DCA selected, but CR conditions were never reached, Ionization Fraction plots would not appear. This has been fixed.
• EOS and Opacity Viewer
  • EOS and Opacity Viewer has also been updated to use Qt 6.2.6.