{"id":"8473114f-cb39-4bbd-ba48-28f03bef3058","arxiv_id":"2509.06848","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":5,"one_line_summary":"A global Sun model with realistic flare-beam heating yields co-generated sunquakes, Moreton-like waves, and coronal fronts, with the Moreton wave's apparent supersonic speed explained by refraction of the faster coronal wave.","lead":"This paper extends a whole-Sun acoustic computer model upward into the corona and uses flare-beam heating from RADYN to excite waves. It shows one particle beam can simultaneously produce a sunquake, a Moreton-like chromospheric wave, and a coronal front, potentially linking three separate solar phenomena to one cause.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The Moreton-analogue result depends on a coronal seed wave whose formation is described via nonlinear 'collision' dynamics, but the model is linearized; the 117 km/s speed may be an artifact of that inconsistency.","rationale":"The central claim has two parts: particle beams can excite sunquakes (supported by prior work and by the interior part of the simulations), and the same beam can excite LCPF/Moreton analogs via acoustic refraction. The second, novel part is load-bearing because the abstract and strongest claim present it as a demonstrated result. The concern is not merely that the real corona is magnetized; the model's own narrative for forming the coronal seed wave uses nonlinear language that the linearized equations cannot represent. Section 4's admission of supersonic amplitudes undercuts the validity of the linearization precisely where the mechanism operates. Thus the 117 km/s number and the amplitude ratios may be artifacts. The reader identified the same broad assumption—linear, adiabatic, non-magnetic acoustic medium—and I partially agree, adding that even within the acoustic model the seed-formation step is nonlinear. The appropriate response is to require a nonlinear/MHD test before treating the atmospheric-wave conclusions as robust, which is exactly the reader's CONDITIONAL verdict. No verdict change is needed; the concern reinforces the conditionality rather than overturning it.","tokens_in":10422,"tokens_out":5013,"duration_ms":58124,"concrete_test":"Run a 2.5D nonlinear MHD simulation using the same RADYN-derived beam heating in a low-beta atmosphere with a realistic background magnetic field, and construct the same time-distance diagnostic at z=500 km. If the apparent chromospheric ridge speed differs substantially from 117 km/s, or no such ridge forms without the artificial linear seed, then the acoustic-refraction mechanism fails. A cheaper first step: rerun the current linear code with the nonlinear advection terms restored (but no magnetic field) and check whether the coronal seed wavefront still forms as described in Section 3; if it does not, the mechanism is internally inconsistent.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The paper's atmospheric conclusion—that a coronal wavefront refracting across the transition region produces a chromospheric disturbance whose apparent 117 km/s speed explains Moreton waves—depends entirely on the existence and geometry of the coronal seed wave. That seed is not a robust consequence of the linearized Equations (1)-(3). Section 3 describes its formation as: upflows 'form an expanding region of over-pressure,' 'outflows collide with the surrounding stationary plasma, increasing the local density,' and the overdense plasma 'falls since hydrostatic equilibrium is lost.' These are nonlinear, advective processes, yet Section 2.1 states that nonlinear perturbations are removed from the expanded equations. A linear calculation cannot genuinely produce a collision or gravitational over-density collapse; it can only superpose acoustic sources. Section 4 admits that the wavefronts have 'supersonic amplitudes' and that shocks are not described by the linear adiabatic model. Because the seed wave's horizontal travel time sets the apparent 117 km/s speed (Figure 4), the central Moreton explanation is not supported by the presented simulations unless the seed is independently established. Additionally, in the low-beta corona the relevant wave is fast magnetosonic, not purely acoustic; its refraction at the transition region depends on field orientation and can undergo mode conversion, so the acoustic-only refraction could change or disappear. The authors call the atmospheric analogies 'purely qualitative,' but the quantitative claims (117 km/s, amplitude ratios, electron vs proton distinctions) are presented as results, making this a load-bearing gap rather than a harmless caveat.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek-v4-flash","summary":"The manuscript extends the semi-spectral 3D acoustic model of Stefan & Kosovichev (2020) upward through the chromosphere and lower corona, and excites it with RADYN-derived heating profiles for power-law proton and electron beams. Two source prescriptions are compared: an acceleration source from RADYN pressure perturbations and a pressure-rate source from volumetric heating. The simulations produce a sunquake, a chromospheric Moreton-like wavefront, and a coronal wavefront. The central interpretation is that the chromospheric wavefront is not truly supersonic; it is a local-sound-speed response to a coronal wave sweeping along the transition region, yielding an apparent horizontal speed of 117 km/s. The paper also reports species-dependent amplitude ratios and photospheric velocity signs, and proposes electron beams as a source of Moreton waves without detectable sunquakes.","tokens_in":10775,"tokens_out":12741,"duration_ms":136987,"significance":"If correct, the paper provides a single beam-driven mechanism that simultaneously produces sunquake, Moreton-like, and LCPF-like waves, and a geometric/sweeping explanation for the apparent supersonic Moreton speed without imposing that speed. The agreement between the two source-injection methods on the main wave pattern is a strength, as is the emergence of the Moreton-like speed from prescribed heating and background stratification. The paper also yields falsifiable, if preliminary, predictions: relative Moreton-to-sunquake amplitudes depend on beam species, and photospheric velocity sign depends on beam species. The main caveat is that the atmospheric conclusions rest on a linear, adiabatic, non-magnetic model whose limitations the authors explicitly acknowledge (Section 4); the significance is therefore conditional on those limitations being quantified or tested with nonlinear MHD simulations.","major_comments":[{"comment":"Section 3 describes the coronal seed wave as produced by an 'expanding region of over-pressure', by outflows that 'collide with the surrounding stationary plasma, increasing the local density', and by overdense plasma that 'falls since hydrostatic equilibrium is lost'. These are nonlinear advective and gravitational descriptions, but Section 2.1 states that 'non-linear perturbations are removed' from Equations (1)-(3). Convergent flows and acoustic-gravity oscillations can be represented linearly, but 'collisions' and the loss of hydrostatic equilibrium as described are not mechanisms available to the linearized system. Since the apparent Moreton speed in Figure 4 is set by this seed wave's travel time, the paper should show that the seed wave is a small-amplitude linear wave of the model, or provide a nonlinear calculation. Section 4's statement that the atmospheric wavefronts have 'sup","section":"Section 3 (seed-wave formation) vs Section 2.1"},{"comment":"The atmospheric and Moreton conclusions are drawn from a purely acoustic model, while observed Moreton and EUV waves are generally understood as fast magnetosonic disturbances in a low-beta corona. The paper itself says the analogies are 'purely qualitative', yet the abstract and Section 4 claim to explain the apparent supersonic nature of Moreton waves. In a magnetized plasma the relevant speed is sqrt(c_s^2 + v_A^2), the transition-region refraction depends on field orientation, and mode conversion changes the wave that reaches the chromosphere. The 117 km/s sweeping mechanism could change or disappear. I request a quantitative estimate of the fast-mode speed stratification for representative coronal field strengths and a discussion of whether the sweeping geometry survives oblique fields, or a clear downgrade of the Moreton claim to a purely acoustic analogue.","section":"Section 4 (non-magnetic approximation)"},{"comment":"Section 4 notes that the coronal wave reflects at the upper boundary despite non-reflecting conditions, and that the Moreton-like wave reflects at the photosphere, exciting additional coronal waves. The time-distance data in Figure 4 extend to 700 s, and the amplitude ratios in Section 3 are measured after the first reflected signals may re-enter the region. The damping scheme was designed for p-modes, not atmospheric waves, so these reflections may contaminate the quoted 117 km/s speed and the Moreton-to-sunquake amplitude ratios. Please mark reflected arrival times on the time-distance diagrams, or perform a sensitivity test with a larger/absorbing domain.","section":"Section 4/Figure 4 (boundary reflections)"},{"comment":"The quoted apparent speed is 117 km/s, but the model's coronal sound speed just above the transition region is 75 km/s and the chromospheric sound speed is 7 km/s; observed Moreton speeds are typically several hundred km/s. The mechanism may scale with the background sound-speed and density stratification, but the paper does not give a scaling law or dimensionless relation. Without this, it is difficult to assess whether the sweeping/refraction explanation is quantitatively relevant to real Moreton waves, whose speeds are set by coronal fast-mode speeds of order 500-1000 km/s. Please provide a scaling estimate in terms of coronal sound speed, transition-region height, and source geometry.","section":"Section 3 (apparent speed scaling)"},{"comment":"The Moreton-analog-to-sunquake amplitude ratios differ substantially between source prescriptions for the same beam species: for protons, 2.3 (acceleration method) versus 10.1 (heating method); for electrons, 12.3 versus 21.1. The conclusion that electron beams may be primarily responsible for Moreton waves without a detectable sunquake is therefore sensitive to the source-injection method, with a factor-of-four spread in the proton case. The paper does not explain which method is more realistic. Please address this sensitivity before using the ratios as observational discriminants.","section":"Section 3 (amplitude ratios)"}],"minor_comments":[{"comment":"Units in the sentence following Eq. (4) are inconsistent: '10^11 cm^-2 s^-1' should read '10^11 erg cm^-2 s^-1' (or be explicitly identified as number flux N0).","section":"Section 2.2, Eq. (4)"},{"comment":"Typo: 'rho0' should be '\\rho_0'.","section":"Eq. (5)"},{"comment":"Text refers to 'the left panel of Figure 3', but the figure caption describes a single panel; if there are multiple panels, label them; otherwise remove 'left panel'.","section":"Figure 3"},{"comment":"The abstract says the domain is extended 'several 10's of Mm above the photosphere', but Section 3 says the top boundary is at 1.5 R_sun. Please state the actual upper boundary in Mm relative to the photosphere and reconcile the two descriptions.","section":"Abstract / Section 3"},{"comment":"Specify how the 117 km/s speed was obtained from the time-distance diagram (least-squares fit to the leading edge? a specified time window?).","section":"Figure 4"},{"comment":"The statement that the fast magnetosonic speed 'changes with height in a similar fashion to the sound speed in the presence of a uniform magnetic field' is not generally true because v_A depends on density stratification and field geometry. Reword or justify.","section":"Section 4"}],"recommendation":"major_revision","confidential_remarks":"The manuscript is within scope and I found no evidence of circularity: the Moreton-like speed is an emergent quantity, and Eq. (6) is the standard ideal-gas relation. The two-source-method agreement is a positive control. My main concern is that the paper's headline atmospheric claims go beyond what a linear, non-magnetic acoustic model can establish. I recommend major revision with an explicit request either to add nonlinear MHD validation (perhaps in a follow-up) or to soften the claims so that the Moreton explanation is presented as a qualitative acoustic analogue, not as the explanation of the observed phenomenon."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Two things to know. First, this is a real step forward in scope: the authors extend their semi-spectral acoustic sunquake model from the interior up through the chromosphere and corona, inject RADYN-derived beam heating, and show, in one simulation, disturbances that look like sunquakes, Moreton waves, and LCPFs. Second, the central Moreton explanation—apparent supersonic speed from a fast coronal wave refracting down through the transition region—is physically plausible and follows Uchida's old idea, but the presented simulations do not actually establish the seed wave they rely on. The stress-test note is right: Section 3 describes the coronal wave as forming from upflow 'collisions' and gravitational collapse of overdense plasma, but Section 2.1 explicitly removes nonlinear perturbations. A linear calculation cannot produce a collision; it only superposes acoustic waves from the prescribed source. So the 117 km/s number and the amplitude ratios are outputs of a mechanism the equations do not contain. That's a load-bearing gap, not a cosmetic caveat.\n\nWhat the paper does well: the two source-injection methods agree on the qualitative wave pattern, which is a meaningful consistency check. The electron-vs-proton difference in Moreton/sunquake amplitude ratio is a testable signature. The authors are unusually candid about the missing magnetic field, radiation, and nonlinear shocks—Section 4 names the problems directly. The writing is clear and the self-citation is legitimate; the earlier Stefan & Kosovichev model is the necessary infrastructure, not the target result.\n\nThe soft spots, in order. First, the linear/nonlinear inconsistency above. Second, in the low-beta corona the relevant wave is fast magnetosonic, not acoustic; refraction across the transition region depends on field geometry and can include mode conversion, so the acoustic-only picture could change or vanish. The authors call the atmospheric analogies 'purely qualitative' but then give quantitative speeds and ratios—that mismatch needs fixing. Third, boundary reflections contaminate the amplitude ratios, and the authors acknowledge this. Fourth, no code or data are provided, so the numerics are not independently checkable.\n\nWho gets value: solar flare and helioseismology researchers interested in sunquake excitation and large-scale wave co-generation. It deserves a serious referee: the concept is important and the limitations are honestly stated. I would send it to review, with the expectation of major revision—specifically, a nonlinear or magnetized test of the seed-wave formation, or an explicit derivation that the linear source alone produces the same refraction pattern. If the authors can close that gap, this becomes a solid paper.","headline":"A genuinely new, clearly explained attempt to unite sunquakes, Moreton waves, and EUV fronts under one beam-driven acoustic model, but the quantitative Moreton result rests on a linear model doing nonlinear work.","tokens_in":11274,"tokens_out":2772,"would_cite":false,"duration_ms":28236,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"Particle beams that make sunquakes also make Moreton waves","keywords":["solar oscillations","sunquakes","Moreton waves","coronal propagating fronts","particle beam heating","transition region refraction","solar flare seismology"],"falsifier":"Run the same beam-heating profiles in a nonlinear magnetohydrodynamic model with a realistic magnetic field: the paper's refraction chain predicts a downward vertical wavefront just below the transition region whose arrival time is set by the coronal sound speed. If the wave instead propagates as a fast magnetosonic shock at the local magnetosonic speed, with no refraction delay, the mechanism is falsified. Observationally, high-cadence H-alpha and EUV Doppler data across a Moreton event should show the chromospheric front's onset delay growing with distance from the source at the coronal-fron","tokens_in":10349,"feed_emoji":"🌞","tokens_out":12125,"duration_ms":125144,"temperature":0.7,"pith_summary":"The paper establishes that a single flare-particle-beam event can simultaneously excite three classes of waves that are usually studied separately: sunquakes in the solar interior, large-scale propagating fronts in the corona, and Moreton waves in the chromosphere. To do this it pushes a semi-spectral 3D acoustic model of the whole Sun up into the transition region and lower corona, and drives the model with height-dependent heating and pressure-perturbation profiles taken from radiative-hydrodynamic flare simulations. The load-bearing result is an acoustic mechanism for the Moreton wave's long-known puzzle: the fast coronal wavefront refracts across the transition region, and every point it touches acts as a new source of a downward chromospheric wave; because the coronal front travels at about 75 km/s while the chromospheric sound speed is about 7 km/s, the chain of downward waves appears to sweep horizontally at roughly 117 km/s. If the mechanism holds, apparent supersonic Moreton waves need no true supersonic chromospheric motion, and Moreton/EUV waves without coronal mass ejections can be explained by beam heating alone.","feed_headline":"Same particle beams launch sunquakes, Moreton waves, coronal fronts","feed_subtitle":"A Sun-wide acoustic model shows coronal waves refracted at the transition region make Moreton fronts look supersonic.","key_machinery":"The central object is a semi-spectral 3D acoustic model of the Sun whose domain is extended upward through the transition region and lower corona. It couples a standard solar interior model to a semi-empirical chromosphere-corona atmosphere model, solves the linear adiabatic wave equations spectrally in horizontal angle and with a fourth-order finite difference in radius, and expands solutions in spherical harmonics up to angular degree 6000 over 1378 radial grid points. The model is driven by two source prescriptions derived from radiative-hydrodynamic flare simulations: an acceleration method using pressure perturbations and a heating method converting volumetric heating into pressure pert","core_discovery":"Using a linear adiabatic acoustic model whose domain extends from the solar interior through the transition region and lower corona, the authors simulate the response to particle-beam energy deposition prescribed by radiative-hydrodynamic flare simulations. For proton and electron beams with a power-law energy distribution, the model produces a sunquake wavefront in the photosphere, a fast outward coronal wavefront, and a chromospheric wavefront whose horizontal track moves at about 117 km/s while the local sound speed in the chromosphere is only about 7 km/s. The apparent supersonic speed is not a chromospheric propagation speed: the coronal wave, traveling at about 75 km/s in the low coron","pith_inferences":["A natural extension is to rerun the same beam-heated source profiles in nonlinear magnetohydrodynamic simulations with a background magnetic field; the refraction chain would survive where the fast magnetosonic speed stratification follows the sound-speed profile and break where it does not.","The electron-beam amplitude ratios imply a specific observational census: events with clear Moreton/EUV fronts but no detectable sunquake should be electron-beam dominated, while strong sunquake events with weak or absent Moreton fronts would point to proton beams.","Because the apparent horizontal speed equals the coronal sound speed at the height where the wave crosses the transition region, the model predicts a measurable correlation between coronal temperature and observed Moreton-wave speed variations across events."],"forward_implications":["A single particle-beam source can excite all three wave classes, so Moreton waves and coronal fronts observed without a coronal mass ejection need not require a different driver.","The Moreton wave's apparent supersonic speed is a projection of the fast coronal wave's horizontal travel, not a real supersonic disturbance moving through the chromosphere.","Electron beams, which in the simulations give weak sunquake signals but strong Moreton-like fronts, predict Moreton/EUV waves unaccompanied by detectable sunquakes; proton beams predict the opposite, offering an observational discriminator.","The sign of the initial photospheric radial velocity beneath the source differs between proton and electron beams, so Doppler observations of sunquake sources could diagnose the beam composition.","The simulated Moreton-analogue wave has a downflow at its leading edge, matching the observed H-alpha red-wing absorption and blue-wing enhancement signature."],"supporting_citations":[{"why":"Supplies the radiative-hydrodynamic beam-heating profiles from which the acoustic source functions are derived.","marker":"J. C. Allred et al. 2015"},{"why":"Supplies the semi-spectral 3D acoustic model and its wave-damping scheme, extended here to the atmosphere.","marker":"J. T. Stefan & A. G. Kosovichev 2020"},{"why":"Supplies the standard solar interior background stratification used in the coupled model domain.","marker":"J. Christensen-Dalsgaard et al. 1996"},{"why":"Supplies the updated semi-empirical atmosphere model background matched to the interior.","marker":"V. Abbasvand et al. 2020"},{"why":"Provides the original coronal fast-mode explanation for Moreton waves that the paper's refraction chain revives in acoustic form.","marker":"Y. Uchida 1968"},{"why":"Is the observational identification of sunquakes that the simulations reproduce.","marker":"A. G. Kosovichev & V. V. Zharkova 1998"},{"why":"Supplies the statistical X-ray correlation that motivates particle beams as sunquake drivers.","marker":"I. N. Sharykin & A. G. Kosovichev 2020"},{"why":"Supplies observed H-alpha Moreton-wave wing signatures that the simulated leading-edge downflow reproduces.","marker":"D. P. Cabezas et al. 2019"},{"why":"Supplies Doppler observations identifying the Moreton leading edge as a downflow or relaxation front, matched by the simulations.","marker":"A. M. Veronig et al. 2011"},{"why":"Supplies the thick-target beam-deposition picture underlying the source modeling.","marker":"G. H. Fisher et al. 1985"}],"fun_headline_variants":["One trigger for sunquakes and coronal waves","Sunquake model spans interior to corona","Coronal waves explain fast Moreton fronts","Particle beams drive sunquakes and fronts","Unified acoustic model links solar layers"],"cache_read_input_tokens":2688,"weakest_assumption_plain":"The load-bearing premise is that the chromosphere and corona behave as a linear, adiabatic, non-magnetic acoustic gas; in the real low-beta solar atmosphere the waves are fast magnetosonic and shock-forming, so the transition-region refraction chain and the 117 km/s apparent speed could differ or disappear.","fun_headline_variants_meta":{"raw":{"variants":["One trigger for sunquakes and coronal waves","Sunquake model spans interior to corona","Coronal waves explain fast Moreton fronts","Particle beams drive sunquakes and fronts","Unified acoustic model links solar layers"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000142,"raw_usage":{"total_tokens":983,"prompt_tokens":703,"completion_tokens":280,"prompt_tokens_details":{"cached_tokens":256},"prompt_cache_hit_tokens":256,"prompt_cache_miss_tokens":447,"completion_tokens_details":{"reasoning_tokens":213}},"tokens_in":447,"tokens_out":280,"duration_ms":4007,"temperature":1.0,"reasoning_tokens":213,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-04T22:58:23.171549+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Run the same beam-heating profiles in a nonlinear magnetohydrodynamic model with a realistic magnetic field: the paper's refraction chain predicts a downward vertical wavefront just below the transition region whose arrival time is set by the coronal sound speed. If the wave instead propagates as a fast magnetosonic shock at the local magnetosonic speed, with no refraction delay, the mechanism is falsified. Observationally, high-cadence H-alpha and EUV Doppler data across a Moreton event should show the chromospheric front's onset delay growing with distance from the source at the coronal-fron","supporting_citations":[{"cited_title":"H., Canfield, R","cited_arxiv_id":null,"evidence_quote":"Supplies the thick-target beam-deposition picture underlying the source modeling."}],"review_version":1}