# Paper Title: "Multi-Machine Scaling Laws for Fuel and Impurity Puffing Rates Sufficient for Detachment Access: a Systematic Review of Magnetic Confinement Fusion Devices" # Database title: "[Database] Multi-Machine Scaling Laws for Fuel and Impurity Puffing Rates Sufficient for Detachment Access: a Systematic Review of Magnetic Confinement Fusion Devices" # Database filename: "MM_puff_database_Zenodo" **Authors:** - M. Moscheni, Gauss Fusion GmbH, ORCID: https://orcid.org/0000-0002-6355-7274 **Contact:** matteo.moscheni@gauss-fusion.com - A. Herrmann - R. Kembleton - M. Kryjak - S. Lazerson - F. Levi - M. Siccinio - P. Staniec - T. Giegerich - C. Tantos **Version:** 1.0.0 **Date:** 2025-07-14 (YYYY-MM-DD) --- ## 1. Overview and Purpose This database contains experimental and numerical data from papers available in the literature. The primary purpose of this dataset is to: - Facilitate research into the operational space for plasma detachment. - Provide empirical data for building and validating scaling laws for detachment access. - Support the development of predictive capabilities for future fusion devices. Each row in the dataset represents a different time instant within a discharge, or different discharges, or different simulations. --- ## 2. File List This repository contains the following files: - `.xlsx`: The primary database file in Microsoft Excel format. - `README.txt` (or `README.md`): This file, providing an overview and detailed explanation of the database. --- ## 3. Data Description (Database Schema / Column Definitions) The main data is contained in `puff_data_v2_Zenodo.xlsx`. Entries marked as WIP*** (work in progress) are tentative, not used in the paper but could be worth including in future developments. The primary sheet is named "puff_data" and contains the following columns: || :------------------------------------------------------------------------------------- | | Column Name | Data Type | Units | Description | Valid range / notes (if useful) || :------------------------------------------------------------------------------------- | | `Machine [-]` | String | - | Unique name of the machine. | - | | `Experimental [-]` | String | - | Whether the data-point is from experiments ('yes') or from simulations ('no'). | 'yes'/'no' | | `Major radius [m]` | Float | m | Machine major radius. | Ad hoc values for linear plasma devices. | | `Minor radius [m]` | Float | m | Machine minor radius. | Ad hoc values for linear plasma devices. | | `Elongation k [-]` | Float | - | Plasma elongation. | - | | `N_div [-]` | Integer | - | Number of divertors. | 1 for single nulls (or very disconnected double nulls), 2 for double nulls (or very connected double nulls). | | `L_div [m]` | Float | m | Divertor length. | Distance between the inner and outer strike point. | | `H_div [m]` | Float | m | Divertor height. | Distance between the X point and the segment of length L_div. | | `R_div [m]` | Float | m | Divertor radius. | Radius of the midpoint of the segment of length L_div. | | `Topology [-]` | String | - | Magnetic topology. | Lower/upper single null (L-/U-SN), with Super-X (+X)., with snowflake (+SF), disconnected double null (L-/U-DDN), double null (DN), linear plasma device (LIENAR), helical stellarator divertor (helical), island stellarator divertor (Island). | | `Targets [-]` | String | - | Divertor target arrangement. | Vertical (V) and horizontal (H). | | `Material [-]` | String | - | Divertor target material. | - | | `Bt [T]` | Float | T | Toroidal magnetic field on axis. | - | | `Ip [MA]` | Float | MA | Plasma current on axis. | - | | `P_in [MW]` | Float | MW | Injected input power. | - | | `P_sol [MW]` | Float | MW | Power crossing the separatrix towards the SOL. | - | | `P_rad [MW]` | Float | MW | Total power radiated. | WIP*** | | `W_E [kJ]` | Float | kJ | Plasma eneregy content. | WIP*** | | `H98 [-]` | Float | - | H98 factor. | WIP*** | | `tau_E [ms]` | Float | ms | Energy confinement time. | WIP*** | | `Mode [-]` | String | - | Plasma confinement mode. | L/H/I | | `Zeff_core [-]` | Float | - | Average effective charge in the core plasma. | WIP*** | | `cZ_sep [-]` | Float | - | Impurity concentration at the separatrix. | WIP*** | | `ne_avg [m^{-3}]` | Float | m^{-3} | Line-average core electron density. | - | | `ne_sep [m^{-3}]` | Float | m^{-3} | Separatrix electron density. | Not defined in linear plasma devices. | | `Te_sep [eV]` | Float | eV | Separatrix electron temperature. | WIP*** | | `D_sep [m^2/s]` | Float | m^2/s | Particle diffusivity at the separatrix. | WIP*** | | `chi_sep [m^2/s]` | Float | m^2/s | Ion=electron heat diffusivity at the separatrix. | WIP*** | | `lq_OMP [mm]` | Float | mm | Measured power fall-off length remapped at outer mid-plane (OMP). | WIP*** | | `ne_div_max [m^{-3}]` | Float | m^{-3} | Peak electron density at the outer target. | WIP*** | | `Te_div_sp [eV]` | Float | eV | Electron temperature at the outer target strike point. | WIP*** | | `Jsat [A/m^2]` | Float | A/m^2 | Peak ion saturation current at the outer target. | WIP*** | | `q_div [MW/m^2]` | Float | MW/m^2 | Peak heat flux at the outer target. | WIP*** | | `p_div [Pa]` | Float | Pa | Sub-divertor neutral pressure. | - | | `Neutral compression [-]` | Float | - | Neutral compression factor from OMP to divertor. | WIP*** | | `Sputtering [m^{-2} s^{-1}]` | Float | m^{-2} s^{-1} | Peak sputtered flux density at outer target. | WIP*** | | `Rollover [-]` | String | - | Whether the data-point is at rollover, i.e. detachment onset (DOD=1) ('yes') or not (nan). | 'yes'/nan | | `D puff location [-]` | String | - | Fuelling location. | Outer/inner mid-plane scrape-off layer (O-/I-MP-SOL), divertor scrape-off layer (DIV-SOL), divertor private flux region (DIV-PFR) | | `Z puff location [-]` | String | - | Impurity seeding location. | Outer/inner mid-plane scrape-off layer (O-/I-MP-SOL), divertor scrape-off layer (DIV-SOL), divertor private flux region (DIV-PFR) | | `Impurity [-]` | String | - | Impurity element being seeded. | An equivalent one is used where impurity mixtures. | | `Z [-]` | Integer | Impurity atomic number. | - | | `D puff [el/s]` | Float | el/s| Electron-equivalent fuelling rate. | [el/s] electrons per second = [at/s] atoms per second (D2 converted to atomic-equivalent) | | `Z puff [at/s]` | Float | at/s | Atom-equivalent impurity seeding rate. | [at/s] atoms per second (molecules converted to atomic-equivalent) | | `Z puff [el/s]` | Float | el/s| Electron-equivalent impurity seeding rate. | [el/s] = Z * [at/s] | | `Puff ratio D/Z [(el/s) / (el/s)] = [-]` | Float | - | Puffing ratio of electron-equivalent puffing rates (D puff / Z puff). | - | | `Comments` | String | - | Where/how/which datum is extracted. | IMPORTANT. | | `BibTex` | String | - | BibTex-style reference. | Initial `@` removed to be compliant with .xlsx. | --- ## 4. Methodology and Data Collection Data only from detached cases at the outer target. Detachment onset = either (i) the appearance of ion-flux/electron-density roll-over or, if unavailable, (ii) electron temperature dropping to ~5eV around the outer strike point, or (iii) when explicitly indicated by the author. Instances more deeply detachedare past such point. More details can be found in the column `Comments`. --- ## 5. Software and Tools The primary database file (`.xlsx`) can be opened with: - Microsoft Excel (2010 or newer recommended) - LibreOffice Calc - Google Sheets and imported into various programming languages (e.g., Python using Pandas, R, MATLAB) for analysis. --- ## 6. Known Issues and Limitations From the perspective of the user, an unbiased, graphic data extraction error (digitisation error) of up to ~15% can be assumed affecting any datum pinpointed in a plot and not explicitly quoted in the text of the parent paper. Also unbiased, though not quantifiable, is any transcription/typographical error. --- ## 8. License This database is made available under the **Creative Commons Attribution 4.0 International (CC BY 4.0) License**. You are free to share and adapt the material for any purpose, even commercially, provided you give appropriate credit, provide a link to the license, and indicate if changes were made. --- ## 9. Acknowledgements This research and database creation were supported by Gauss Fusion GmbH. --- ## 10. Citation If you use this database in your research or publications, please cite it as: M. Moscheni et al. (2025). "[Database] Multi-Machine Scaling Laws for Fuel and Impurity Puffing Rates Sufficient for Detachment Access: a Systematic Review of Magnetic Confinement Fusion Devices" (Version 1.0.0). Zenodo. [DOI: 10.5281/zenodo.15878965]