{"id":"cceba42b-5ecb-4438-a4bf-a2f2b7f3ca60","arxiv_id":"2607.11901","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":4,"one_line_summary":"Direct detection of runaway electrons up to 45 MeV in TGEs occurs only under rare low cloud-base (~45 m), near-0°C mixed-phase conditions that let electrons survive to the detector.","lead":"Six thunderstorm events at Aragats show high-energy electrons (to 45 MeV) reaching ground only when cloud bases sit tens of meters overhead. This explains why Wilson's century-old runaway electrons were almost never seen directly: electrons die in air unless the accelerator is unusually close.","discovery_kind":"extension","skeptic_critique":{"model":"grok-4.5","headline":"Cloud-base proxy may not equal RREA path length; height formula alone does not secure the geometric claim.","rationale":"The Reader correctly isolates the load-bearing assumption: that the SPREAD cloud-base formula plus near-0 °C temperatures place the active RREA region only tens of meters above the detector. The paper’s strongest claim is explicitly geometric (“only when the active acceleration region approaches within several tens of meters”), and every supporting table and figure (Tables 1–2, Fig. 3) uses that proxy. The charged/neutral separation and exponential spectra to ~45 MeV are solid observational results, but they do not by themselves prove the path-length interpretation; the archive contrast only shows that electron-rich events are rare and meteorologically clustered, not that Hcloud is the controlling distance. Because the concern is precisely the one the Reader flagged, and because independent height data would settle it without requiring rejection of the whole dataset, the verdict remains CONDITIONAL and agreement is full. No stronger internal contradiction is present.","tokens_in":9321,"tokens_out":566,"duration_ms":10870,"concrete_test":"For the six events, recompute or obtain independent cloud-base / charge-layer heights (ceilometer, radar, or multi-station electric-field inversion) and re-plot electron significance vs. those heights; if the tight clustering at ≲ 50 m disappears or the correlation with electron fraction weakens substantially relative to the SPREAD values in Table 2, the geometric explanation for rarity loses its main empirical support.","verdict_should_be":"CONDITIONAL","load_bearing_attack":"The central claim—that Wilsonian electrons are observed only when the acceleration region is within tens of meters of the detector—rests on identifying Hcloud = 122 × (T − Td) (Method §2, Eq. 1; Tables 1–2) with the vertical path length through the RREA region. All six events have Hcloud 25–87.5 m (mean 44.7 ± 19.6 m) and T ≈ 0 °C, and the archive contrast is used to argue that only this geometry lets electrons survive. That identification is the weakest link: the formula estimates the lifting-condensation level of surface air, not the altitude of the charge layer or the actual electron-production volume. A higher or laterally offset mixed-phase region with a strong vertical field could still deliver electrons if the field geometry or local density allows, while a low LCL does not guarantee that the RREA volume itself sits only tens of meters above the roof. Without independent height diagnostics, the “only when \to tens of meters” causal statement remains a proxy inference rather than a measured path length.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.5","summary":"The manuscript reports six electron-rich Thunderstorm Ground Enhancements (TGEs) recorded at Aragats (3200 m) with the SEVAN-Light spectrometer, which separates charged and neutral particles via coincidence logic and reconstructs electron energy spectra by GEANT4 unfolding. The events show statistically significant electron enhancements (mean ~18.6%, ~16.8σ), exponential spectra with characteristic energies E0 ~ 6.3–8.6 MeV and maximum reconstructed energies up to 45 MeV, and occur under a compact set of conditions: cloud-base heights estimated at 25–87.5 m (mean 44.7 ± 19.6 m), surface temperatures near 0 °C, strong near-surface electric-field disturbances, and frequent nearby lightning (often terminating the flux). Comparison with the 2012–2025 Aragats TGE archive is used to argue that direct detection of Wilsonian/runaway electrons becomes possible only when the acceleration region approaches within several tens of meters of the detector, thereby explaining the century-long rarity of such observations.","tokens_in":9536,"tokens_out":1469,"duration_ms":10812,"significance":"If the geometric interpretation holds, the paper supplies a concrete experimental resolution of a long-standing observational paradox in high-energy atmospheric physics: why gamma-ray glows and TGEs are common while direct electron detections remain rare. The combination of charged/neutral separation, spectral unfolding to tens of MeV, multi-parameter event tables, and archive contrast is a genuine strength of the Aragats program and would establish a distinct near-ground RREA regime. The work is therefore of clear interest for models of RREA, TGFs, lightning initiation, and natural particle acceleration, provided the identification of cloud-base proxy with electron path length is tightened or appropriately caveated.","major_comments":[{"comment":"Method §2, Eq. (1) and Tables 1–2: The central claim that electrons are observed “only when the active acceleration region approaches within several tens of meters” rests on equating Hcloud = 122 × (T - Td) with the vertical path length from the RREA volume to the detector. The formula estimates the lifting-condensation level of surface air, not the altitude of the charge layer or the electron-production region. A higher or laterally offset mixed-phase structure could still deliver electrons under suitable field geometry. Without independent height diagnostics (ceilometer, radar, or multi-station timing) or a quantitative attenuation calculation that maps Hcloud to surviving electron flux, the causal “only when … tens of meters” statement remains a proxy inference. The claim should be restated as a necessary meteorological association or supported by additional height/attenuation evidenc","section":null},{"comment":"§3.1–3.2 and archive comparison: The electron-rich sample comprises only six events, while the archive contrast uses a 15% two-sided trim on temperature, cloud-base, and lightning distance. With such a small selected class, the reported compactness (mean Hcloud 44.7 ± 19.6 m, T = 0.0 ± 1.3 °C) and the factor-of-2.5 difference relative to the archive central population need a clearer statistical treatment (selection completeness, false-positive rate for the coincidence channel, and sensitivity of the trim). Otherwise the geometric uniqueness argument is under-powered relative to the strength of the abstract and conclusions.","section":null},{"comment":"§2 detector response and §3.3 spectral recovery: The “11” coincidence is stated to be predominantly electrons (efficiency 60–99% for 10–50 MeV, gamma contamination 0.8–1.8%), yet residual gamma contamination and any muon contribution at these energies are not quantified event-by-event after unfolding. Because the claim of direct Wilsonian-electron detection is load-bearing, a short contamination budget (or upper limit) for the unfolded spectra in Figure 2 / Table 2 should be provided so that the 37–45 MeV endpoints cannot be attributed to residual neutrals or systematics.","section":null}],"minor_comments":[{"comment":"Figure 1 caption and layout: The multi-panel description (“panels a-b”) is hard to parse for six events; label each event explicitly and ensure NSEF polarity and lightning-termination markers are legible.","section":null},{"comment":"Table 1: Mean/RMSD row for NSEF is left blank (“-”) while other columns report values; either compute the mean/RMSD or state why polarity precludes a simple average.","section":null},{"comment":"Table 2 vs. Table 1: Cloud-base heights differ slightly (e.g., 85.4 m vs. 87.5 m for TGE1) because of rounding of T-Td; note the source of the difference or use a single consistent value.","section":null},{"comment":"References: Several 2026 items are listed as “in press”; ensure they are citable or replace with DOIs/preprints where available. Heavy self-citation of the Aragats series is understandable but a few independent RREA/TGF reviews would improve balance.","section":null},{"comment":"Plain-language summary and abstract: Phrases such as “century-long rarity” and “experimental explanation” are strong; once the geometric claim is caveated, align the wording so that the summary does not over-state the path-length identification.","section":null},{"comment":"Notation: SEVAN-Light / SEVAN Light and “Wilsonian electrons” / “runaway electrons” alternate; pick consistent forms. Also define LADC and NSEF at first use in the main text.","section":null}],"recommendation":"major_revision","confidential_remarks":"The charged/neutral separation and spectral work are solid and within the Aragats group’s established expertise; the main risk is over-claiming that the LCL proxy equals RREA path length. If the authors moderate the causal language and add a contamination/attenuation discussion, the paper becomes a useful observational contribution. Scope fits atmospheric electricity / high-energy atmospheric physics journals; novelty is incremental relative to prior Aragats electron claims but the six-event spectral set and archive contrast add value."},"author_rebuttal":null,"desk_editor":{"model":"grok-4.5","letter":"The useful core is six SEVAN-Light TGEs with charged/neutral separation and unfolded electron spectra to ~45 MeV, all sitting in a tight meteorological pocket (cloud base ~25–87 m, T near 0 °C, strong NSEF, often lightning-terminated). That is cleaner than most prior Aragats electron claims and gives a concrete observational answer to why Wilsonian electrons have been rare: electrons only survive when the source is tens of meters away.\n\nWhat they do well is the detector logic and the archive contrast. The “11” vs “01” coincidences, efficiency numbers, and GEANT4 unfolding produce stable exponential spectra (E0 ~6–9 MeV). Event selection is multi-channel plus |NSEF| > 5 kV m⁻¹, so electron richness is not just a bright-TGE cut. The 2012–2025 comparison shows these six sit well below the typical cloud-base population. Data are on ADEI; the tables are transparent.\n\nThe soft spot is real but not fatal. Hcloud = 122(T−Td) is an LCL estimate, not a lidar/radar height of the charge layer or the RREA volume. Low LCL plus mixed-phase temperature makes a short path length likely, but it does not prove the acceleration region itself is only tens of meters above the roof. Lateral offset or a higher layer with favorable field geometry remains possible. Sample size is six; response-matrix details live mostly in prior papers. Those are the right caveats, not reasons to dismiss the result.\n\nThis is for people who work on TGEs, TGFs, RREA, and lightning initiation. It is observational, not a new theory paper. Math and spectral fits look ordinary and solid; citations are heavy on the Aragats program but also engage the recent debate (Williams, Mailyan, etc.). I would send it to referees. Ask for independent height diagnostics or clearer language that the path-length claim is proxy-based, and for fuller public response matrices. Worth engaging.","headline":"Solid multi-event electron spectra under low cloud bases; the geometric rarity claim is plausible but rests on a proxy height, not a measured path length.","tokens_in":10244,"tokens_out":500,"would_cite":true,"duration_ms":4702,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.5","headline":"Runaway thunderstorm electrons reach detectors only when the cloud base drops to tens of meters above the ground.","keywords":["thunderstorm ground enhancements","Wilsonian electrons","relativistic runaway electron avalanches","cloud-base height","charged-neutral separation","near-surface electric field","electron energy spectra","atmospheric particle acceleration"],"falsifier":"A statistically significant electron-rich TGE recorded by the same charged/neutral spectrometer while independent ceilometer or lidar measurements place the cloud base hundreds of meters or more above the station would falsify the geometric-proximity requirement.","tokens_in":10127,"feed_emoji":"⚡","tokens_out":951,"duration_ms":9033,"temperature":0.7,"pith_summary":"For a century, strong thunderstorm electric fields have been expected to accelerate electrons to relativistic energies, yet the electrons themselves have almost never been caught at the surface while the gamma rays they produce are routinely seen. This paper reports six electron-rich thunderstorm ground enhancements in which a spectrometer that separates charged from neutral particles recovers electron spectra reaching 45 MeV. Every one of those events occurred under the same narrow set of conditions: cloud base only a few tens of meters above the detectors, surface temperatures near 0 °C, strong near-surface electric-field disturbances, and nearby lightning. Comparison with the full multi-year archive of ordinary (mostly gamma-dominated) events shows that electron survival is controlled by propagation distance. The long-standing rarity is therefore geometric rather than physical: the electrons are produced, but they are absorbed before they can reach ordinary detector altitudes unless the acceleration region itself descends almost to the ground.","feed_headline":"Thunderstorm electrons reach ground only when clouds drop to tens of meters","feed_subtitle":"Six events show why Wilson’s runaway electrons stayed invisible for a century: geometry, not absence","key_machinery":"SEVAN-Light charged/neutral coincidence spectrometer plus cloud-base height Hcloud = 122 × (T − Td). Coincidence logic isolates the electron component; the height formula, together with near-0 °C temperatures, places the mixed-phase charge-separation region only tens of meters above the station, short enough for multi-tens-of-MeV electrons to reach the detector.","core_discovery":"Direct ground-level detection of Wilsonian runaway electrons becomes possible only when the active acceleration region lies within several tens of meters of the detector (mean cloud-base height 44.7 ± 19.6 m for the six events). Under those rare near-ground conditions the electrons survive atmospheric attenuation, produce measurable charged-particle fluxes up to 45 MeV, and exhibit stable exponential spectra, thereby explaining why such detections have remained exceptional for a century.","pith_inferences":["Sites that routinely experience low mixed-phase cloud bases at high altitude should show a higher fraction of electron-rich TGEs than low-elevation stations.","If the geometric condition is universal, satellite or aircraft TGF observations may still miss the bulk electron population for the same attenuation reason.","Coordinated ceilometer–spectrometer campaigns during spring and autumn transition storms would provide the cleanest test of the height threshold.","The same proximity requirement may explain why early twentieth-century searches for Wilson electrons failed even when gamma-ray glows were later found to be common."],"forward_implications":["Most historical and future ground-based TGE searches will remain gamma-dominated unless instruments are placed under unusually low mixed-phase cloud bases.","Models of relativistic runaway electron avalanches must treat a distinct near-ground regime in which both electrons and photons survive to detector altitude.","Lightning termination of four of the six events supplies direct evidence that the avalanche is controlled by the pre-discharge electric-field structure.","Stable exponential spectral shapes with characteristic energies of 6–9 MeV across events of very different intensity imply a common acceleration mechanism whose main variation is avalanche multiplication.","The atmospheric conditions required for direct electron detection are now observationally defined and can be used to design targeted campaigns."],"fun_headline_variants":["Wilsonian electrons hit ground only when clouds drop to tens of meters","Runaway electrons reach detectors only under near-surface storm clouds","Ground detection of Wilson electrons needs clouds within tens of meters","Thunderstorm runaway electrons survive only if acceleration is tens of meters up","Low cloud bases of ~45 m enable direct sightings of Wilsonian electrons"],"cache_read_input_tokens":128,"weakest_assumption_plain":"The claim rests on the premise that the simple temperature–dew-point formula, together with near-freezing surface air, truly locates the runaway-electron acceleration region only tens of meters above the detectors rather than higher or laterally offset.","fun_headline_variants_meta":{"raw":{"variants":["Wilsonian electrons hit ground only when clouds drop to tens of meters","Runaway electrons reach detectors only under near-surface storm clouds","Ground detection of Wilson electrons needs clouds within tens of meters","Thunderstorm runaway electrons survive only if acceleration is tens of meters up","Low cloud bases of ~45 m enable direct sightings of Wilsonian electrons"]},"model":"grok-4.5","effort":"low","cost_usd":0.004874,"raw_usage":{"total_tokens":1323,"prompt_tokens":718,"num_sources_used":0,"completion_tokens":92,"cost_in_usd_ticks":48740000,"prompt_tokens_details":{"text_tokens":718,"audio_tokens":0,"image_tokens":0,"cached_tokens":128},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":513,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":718,"tokens_out":92,"duration_ms":4220,"temperature":1.0,"reasoning_tokens":513,"cache_read_input_tokens":128,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-07-15T10:26:07.445189+00:00","model_set":{"reader":"grok-4.5"},"falsifier":"A statistically significant electron-rich TGE recorded by the same charged/neutral spectrometer while independent ceilometer or lidar measurements place the cloud base hundreds of meters or more above the station would falsify the geometric-proximity requirement.","supporting_citations":[],"review_version":1}