High-γ Charge Field and EO Workbench

01What the experiment records

Ota et al. (2022) studied spatiotemporal fields around a relativistic electron beam through optical modulation in electro-optic sampling. The paper specifies a 35 MeV beam and discusses possible instrumental causes of a measured peak below the calculation. That discrepancy is not ASD evidence.

The paper states that data and code are available from the corresponding author on reasonable request. No raw time series, calibration files or complete reproduction code have been acquired here; no author contact or fit is claimed.

02From source field to signal

An operational linear small-signal interface is

$S(t)=G\int d\tau\int d^3x\;R(t-\tau,\mathbf x;\eta)E_{\rm lab}(\mathbf x,\tau)+B(t).$

This defines a response integral, not a new ASD field equation. $R$ contains crystal, laser and sampling response; $G$ is independently calibrated gain and $\eta$ instrument parameters. Nonlinear, dispersive or nonstationary responses require appropriate extensions. Each theory supplies $E_{\rm lab}$ through the same apparatus chain before comparing $S(t)$. Theory-dependent calibration must also be propagated.

03Strict limits of the current baseline

The workbench computes only the standard normalized transverse field of a uniformly moving point charge, $[1+(\gamma\beta ct/b)^2]^{-3/2}$, followed by an assumed Gaussian temporal kernel. It omits the real 3D bunch, ZnTe dispersion, phase matching, reflections, conductor boundaries, irradiation and optical transfer. It checks how response changes a waveform; it is not an Ota reproduction.

04Required joint calculation

First reproduce the paper's standard source and recorded signal; then independently calculate the general ASD moving source and laboratory mapping. Freeze bunch inputs, time zero, gain and noise covariance, and compare full waveform, width, sign and spatial scans. Do not multiply an EO readout by a co-moving parallel-charge force ratio. Advance OP-EM-001 and OP-EM-004 separately.

Reference constants: PDG 2024 electron.