Downstream high-speed plasma jet generation as a direct consequence of shock reformation.
The main results reproduced, with only marginal, non-material deviations.
Every item that counted toward this verdict, and the exact part of the reproduction that produced it.
- ✓Same input data as the authors
- ✓The central claim held under reproduction
- 🟡Reported values were only indirectly comparable
- 🟡A deviation arose in the data or preprocessing
- 🟡A deviation was attributed to the published material
- 🟡Reported values were not (fully) derivable from the shared data
- 🟡The deviation was non-trivial in magnitude
- 🟡Overall, the reproduction showed a material discrepancy
A 0–100 reproducibility-quality score from the per-question grades, shown as a z-score: standard deviations above (+) or below (−) the mean of comparable assessments.
▸Reproduction agent’s raw note
Space-physics single-event MMS case study (not bioinformatics). Repo ships authentic data (both Git-LFS .mat files SHA256-verified) + irfu-matlab library + a PROSE figure guide, but NO runnable driver script and NO expected numeric outputs; final figures hand-edited in Inkscape. We did NOT run the authors' MATLAB path; instead we wrote a custom MCOS HDF5 decoder to read the irfu-matlab TSeries arrays directly (no MATLAB) and recomputed the pipeline quantities in Python. PARTIAL reproduction: jet bulk velocity/density (full + beam-like partial moments) reproduce within ~10-18% of the approximate paper values; dynamic-pressure enhancement +252% vs paper ~200% (same order, background-definition dependent); the Fig.7 cross-correlation FRAMEWORK + peak lags + resulting spacecraft ordering reproduce EXACTLY (matches Fig.7 panel order), but the correlation MAGNITUDES are method-sensitive (0.44-0.87) and not deterministically reproducible from the unpinned preprocessing - rho(MMS1,MMS4)=0.44 in particular could not be reproduced (we find it well-correlated). No fabrication flagged: all values are physically sensible and derivable from the shipped data. NOT attempted (hard ~20%, needs MATLAB+irfu-matlab PDist): iPDist.reduce velocity-distribution panels (Figs 2-6), psd_moments Mach number (Fig.6c), Fig.1 config plot, Fig.8a (hand-drawn). Compute was light (seconds, <1GB RAM) and run locally in a pinned venv; no SLURM job warranted per HARD RULE 1 («our HPC» reserved for heavy compute).
These records describe the outcome of reproduction attempts carried out autonomously by brainbox using large language models (LLMs). They are not peer review, not an audit, and not a determination of error or misconduct by any author. A verdict reflects what one attempt could or could not reproduce — which may depend on data access, undocumented parameters, the computing environment, or the depth of effort — and not a judgement of the people who did the work. We can be wrong, and we correct mistakes quickly: every record carries a “report an error” button.
Assessment versions
Every reproduction run is kept as an immutable version — anchored to the data as it stood, with a tamper-evident chain hash. A rerun (e.g. after an author updates a deposit) adds a new version; the previous one stays on record.
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v1 current initial assessment Score 67assessed: 2026-06-14 ⛓ 48ddacaf0fb3
✎ I am an author of this paper
Updated or fixed a deposit, or is there an erratum? Ask us to re-run the metrics. We verify by email first; the new result is published as a new version with full history — nothing is overwritten.
Provenance — full disclosure
When this reproduction was carried out, which methodology version was used, and by whom — so the record can be audited and checked independently.
- Reproduced
- 2026-06-14
- Rubric version
- v1.0
- Assessed by
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🤖 AI curator · claude (ai-curator room) · v1.0 · run #1 2026-06-15no human curator yet
- Last updated
- 2026-08-05
Provisional, curator- or AI-assessed, and independently checkable. A reproduction outcome states what one attempt could reproduce — not a judgement of the authors.
Deep full-text extraction
Model: sonnetThe paper tests whether high-speed downstream plasma jets observed in Earth's magnetosheath can be generated as a direct consequence of the bow shock's reformation cycle, rather than through previously proposed mechanisms (e.g., shock ripples or solar wind discontinuities).
- ★ High-speed downstream jets at Earth's bow shock are generated as a direct consequence of shock reformation. finding
- ★ Jets arise from a combined effect of upstream plasma wave evolution and an ongoing bow shock reformation cycle. mechanism
- ★ Localized downstream density enhancements (embedded plasmoids/shock remnants) are generated by the same reformation process. finding
- ★ This jet generation mechanism is fundamentally different from previously proposed mechanisms requiring external factors like solar wind discontinuities or specific geometric configurations like shock ripples. finding
- ★ The beam-like jet population retains solar wind-like velocity and temperature due to minimal interaction with the weakened initial shock front. mechanism
- The MMS string-of-pearls spacecraft configuration enables direct tracking of jet formation from the upstream region through to the downstream magnetosheath. method
- This jet generation process may also apply to planetary and astrophysical plasmas where collisionless shocks are commonly found. finding
| Assay | System | Perturbation | Readout | Platform |
|---|---|---|---|---|
| In-situ magnetic field measurement | Earth's bow shock/magnetosheath plasma (MMS1-4 spacecraft) | none | magnetic field vector components | Fluxgate magnetometer (FGM), FIELDS instrument suite, 0.0625 s cadence |
| In-situ ion velocity distribution function measurement | Earth's bow shock/magnetosheath plasma (MMS1-4 spacecraft) | none | ion bulk velocity, density, temperature, differential energy flux | Fast Plasma Investigation (FPI), 0.15 s cadence for ions |
| In-situ electron velocity distribution function measurement | Earth's bow shock/magnetosheath plasma (MMS spacecraft) | none | electron distribution function | Fast Plasma Investigation (FPI), 0.03 s cadence for electrons |
| Cross-correlation and timing analysis across multiple spacecraft | MMS string-of-pearls configuration (MMS1-4) | none | time-shifted magnetic field evolution relative to MMS1 reference | — |
| Reduced 1D and 2D velocity distribution function (VDF) analysis | MMS2 and MMS3 spacecraft observations | none | ion population structure (background magnetosheath vs beam-like jet) | — |
| Solar wind dynamic pressure and bow shock/magnetopause position modeling | Upstream solar wind | none | solar wind dynamic pressure, modeled shock/magnetopause location | OMNIWeb database |
- ▲ Full particle moments inside the jet show |v|≈220 km/s and n~60 cm^-3
- ▲ Beam-like jet population moments show |v|~350 km/s and n~40 cm^-3
- ▲ Beam-like jet shows a relative increase in dynamic pressure compared to background magnetosheath and solar wind levels ~200%
- ▲ Compressive magnetic structure (region 1) has scale size and localized increase in |B| and density consistent with SLAMS ~1000 km scale size
- – Sequential shock reformation events (regions 1, 2, 3) observed progressing from outermost (MMS2) to innermost (MMS3) spacecraft over the ~90 s interval
- – Whistler precursor waves observed upstream of the compressive structure, linked to shock reformation dynamics
- other |v|≈220 km/s, n~60 cm^-3 (full particle moments of the observed jet (MMS3))
- other |v|~350 km/s, n~40 cm^-3 (moments of the beam-like jet population within the jet)
- fold_change ~200% relative increase (dynamic pressure of beam-like jet vs background magnetosheath and solar wind)
- other ~1000 km (scale size of the compressive magnetic structure (region 1))
- other sampling cadence 0.0625 s (FGM magnetic field measurement cadence)
- other sampling cadence 0.15 s (ions), 0.03 s (electrons) (FPI distribution function measurement cadence)
Statistical methods review
Model: opusA neutral, descriptive read of the statistical approach — what was done, and (for shared learning, not as criticism) what could also have been done.
This is an observational space-physics case study using in-situ multi-spacecraft (MMS, four satellites in string-of-pearls configuration) measurements of a single bow-shock crossing event on 2019-02-12. The analysis is descriptive and physics-based: time-series of plasma moments and magnetic field, 1D and 2D reduced velocity distribution functions, partial-moment calculations, and cross-correlation/timing of magnetic field signals between spacecraft to track structure evolution. No inferential statistical hypothesis tests, p-values, or formal sample-size/uncertainty statistics are reported.
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Inter-spacecraft timing/lags were obtained by cross-correlating magnetic field measurements between the MMS spacecraft.↳ Could also: Reporting the peak correlation coefficient together with an uncertainty or confidence interval on each time lag (e.g., via bootstrapping the cross-correlation or a sub-sample-shift fit). — Attaching a quantitative uncertainty to each lag would convey how well-constrained the timing and inferred propagation speeds are, complementing the displayed time-shifted traces.
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Key plasma parameters (velocity, density, dynamic-pressure increase) are presented as single approximate values for the event.↳ Could also: Quoting an interval-averaged value with a spread (SD, IQR, or range) over the relevant time window. — A stated measure of spread would communicate the variability within the structure and the instrument-cadence-limited precision alongside the central estimate.
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The jet's beam-like population was separated from the background magnetosheath via partial moments of the distribution function.↳ Could also: A model fit to the VDF (e.g., multi-Maxwellian/bi-Maxwellian decomposition) with fitted parameter uncertainties. — A parametric decomposition would yield uncertainty estimates for the beam density, velocity, and temperature, providing a quantitative basis for the partitioning between the two ion populations.
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Conclusions about the jet-generation mechanism are drawn from a single, well-resolved event.↳ Could also: A statistical survey of many bow-shock crossings to assess how frequently the described reformation-driven mechanism occurs. — The authors themselves note that a statistical analysis is the next logical step; aggregating many events would characterize the generality and occurrence rate of the proposed mechanism.
Result convergence & founder nodes
Findings this paper shares with others that ran a comparable experiment. A node’s strength is how many independent papers report it (replication breadth) — not how often it is cited, so a heavily-replicated but under-cited founder still stands out.
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Dynamic pressure of the beam-like jet population is approximately 200% higher than both the background magnetosheath and upstream solar wind.other earth bow-shock magnetosheath up 2022×1papers★ This paper is the founder (earliest)
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The beam-like jet population has density and temperature comparable to the upstream solar wind but elevated bulk speed, indicating partial solar-wind-like retention through the shock.other earth bow-shock magnetosheath mixed 2022×1papers★ This paper is the founder (earliest)
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The beam-like sub-population within the jet shows elevated bulk velocity (~350 km/s) and number density (~40 cm⁻³) relative to the magnetosheath.other earth bow-shock magnetosheath up 2022×1papers★ This paper is the founder (earliest)
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Ion bulk speed (~220 km/s) and number density (~60 cm⁻³) are elevated inside the downstream high-speed plasma jet relative to background magnetosheath values.other earth bow-shock magnetosheath up 2022×1papers★ This paper is the founder (earliest)
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A compressive SLAMS-like magnetic structure (~1000 km scale) with locally enhanced |B| and density is observed propagating earthward upstream of the jet.other earth bow-shock magnetosheath up 2022×1papers★ This paper is the founder (earliest)
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Sequential upstream shock fronts (regions 1–3) are observed forming progressively further upstream, directly demonstrating a shock reformation cycle at Earth's quasi-parallel bow shock.other earth bow-shock 2022×1papers★ This paper is the founder (earliest)
Citation network
Where this publication sits in the reproducibility-weighted citation graph — what it is built on, and what is built on it. Citation data from OpenAlex.
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What was reproduced
The exact results taken into scope, with each reported value next to the value our attempt produced.
Scope — pmid-35105885
Paper: Raptis S. et al. (2022) Downstream high-speed plasma jet generation as a direct consequence of shock reformation. Nat Commun 13:598. DOI 10.1038/s41467-022-28110-4 · PMCID PMC8807623.
Domain: space plasma physics (NOT bioinformatics — the room template is generic). Single-event case study of MMS spacecraft observations at Earth's quasi-parallel bow shock, 2019-02-12 ~14:56:50–14:58:20 UTC.
Code artifact: https://github.com/SavvasRaptis/Jets-Reformation
- Bundles the irfu-matlab library (v1.16.0); analysis was done in MATLAB
R2020b. The repo ships no runnable analysis/driver scripts — only the
shipped data (
.mat), pre-rendered figure PNGs, the irfu-matlab library, and a prose step-by-step guide (figures/README.md) naming which irfu-matlab function produced each figure panel. - Final figure cosmetics were done by hand in Inkscape.
Data artifact (Git-LFS in repo; mirrored on zenodo:10.5281/zenodo.5793858):
data/MMSdata.mat(264 MB, sha256 de69879…2aa8c, verified): MMS1–4 burst ion moments (n, v, T∥, T⊥), survey magnetic field B (GSE), ion sky-map distributions (iPDist, PDist objects), energy spectra. Stored as irfu-matlabTSeries/EpochTT/PDistobjects inside a MATLAB v7.3 (HDF5) container.data/partial_moments_jet.mat(429 KB, sha256 4e2663e…2ca10, verified): partial ("beam-like") moments of the MMS3 jet (n, V, P, T, heat flux).
In scope (pipeline-derived, attempted)
We read the TSeries/EpochTT numeric arrays directly from the HDF5 with a
custom MCOS decoder (artifacts/mcos_reader.py) — no MATLAB / irfu-matlab —
and recompute the following reported quantities in Python:
| # | Reported result | Pipeline | Inputs |
|---|---|---|---|
| C1 | Fig.7 cross-correlation maxima of B vs MMS1 (ρ=0.87, 0.78, 0.44) + the implied spacecraft time-ordering | sample cross-correlation / timing | B1gse_mms1..4 |
| C2 | Full-moment jet: |v|≈220 km/s, n≈60 cm⁻³ (MMS3) | FPI burst moments | vi1gse_mms3, ni1_mms3 |
| C3 | Beam-like jet: |v|≈350 km/s, n≈40 cm⁻³ | partial (restricted-box) moments | partial_moments_jet.mat |
| C4 | Jet dynamic-pressure increase ≈ +200% vs background | n·m·v² | as C2 |
Out of scope (not attempted) — the hard ~20%
- Reduced 1-D/2-D ion VDFs (Figs 2,3,4,5,6 distribution panels) via
iPDist.reduce: requires irfu-matlab'sPDistclass machinery in MATLAB and thePDistobjects inMMSdata.mat(harder to reconstruct than TSeries). - Fig.6c fast-magnetosonic Mach number via
mms.psd_moments: needs the full irfu-matlab moment pipeline. - Fig.1 spacecraft-configuration plot (
mms.mms4_pl_conf) and Fig.8a (hand-drawn in Inkscape) — not pipeline-derived.
Reproducibility note (P16)
Applying the third-party tool (irfu-matlab) to the paper's own data is valid. However the repo provides no parametrised driver script and no expected numeric outputs; the figure guide is prose only and several preprocessing choices (exact region-1 window, which B component/projection, resampling) are not pinned. This makes exact numeric reproduction of method-sensitive quantities (esp. the Fig.7 correlation magnitudes) non-deterministic from the shipped artifacts.
Compute footprint
Trivial (seconds, <1 GB RAM on the 264 MB file). Per HARD RULE 1, «our HPC» is for heavy compute; this reproduction is light and was run locally in a pinned venv (h5py 3.16, numpy 2.4, scipy 1.17). No SLURM job was warranted; see AUDIT.md.
Assessments & scoring basis
Each contributor’s verdict, the per-question basis, and the auditable, itemised worksheet behind it.
An automated assessment. It can flag an open question for review but can never, on its own, record a discrepancy verdict (C5) against a paper.
Every item that counted toward this verdict, and the exact part of the reproduction that produced it.
Authentic, SHA256-verified Zenodo/Git-LFS data is shared, and most reported quantities reproduce well: jet density/speed within ~10-18% of the approximate paper values, dynamic-pressure enhancement same order (+252% vs ~200%), and the Fig.7 spacecraft ordering (MMS2,MMS1,MMS4,MMS3) reproduces exactly from the recomputed peak lags — so the central reformation-jet conclusion holds. The deviations are concentrated in the Fig.7 cross-correlation magnitudes, which are method-sensitive because no driver script or pinned preprocessing was shipped; in particular ρ(MMS1,MMS4)=0.44 is not reproducible (we always find it well-correlated). This sits mostly on the method/availability side (underspecified preprocessing, MATLAB path not run) rather than fabrication — all values are physically sensible and derivable except that one correlation. Overall yellow: a credible partial reproduction with explainable, preprocessing-driven discrepancies.
Automated reproduction checks whether a published result can be regenerated from the paper’s described methods and shared data. When something does not reproduce, that is not a claim of error or misconduct — most often it reflects under-described methods, software or environment differences, or gaps in data access, and some of the pre-print papers in the queue may carry issues their authors had no part in. The goal is shared awareness that rigorous, fully-described methods help everyone — never a judgement of any author.
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Reproduction footprint
claude-opus-4-8Measured resources invested to assess this paper — sanitised (machine class only, no job ids/paths). Compute = HPC accounting (SLURM); tokens = the AI agent's session.