We explored the generation and diagnosis of high-brightness MeV bremsstrahlung radiation caused by intense beam of relativistic electrons propagating in a tantalum converter. The intense electron beam was produced through direct laser acceleration mechanism in the interaction of relativistic high-power sub-ps laser pulse with near critical density plasma. We propose to detect the divergence angle and photon fluence of high-brightness and high-energy y radiation source based on the nuclear activation method. The radioactive 62 29Cu was generated through photonuclear reactions 6329Cu(y, n) 6229Cu and the subsequent fi+ decay of 6229Cu was measured to derive characteristics of the y radiation source. This method provides an express approach to diagnose the laser-driven MeV radiation source and a potential efficient way to produce 62 29Cu isotopes.

Warm dense matteris an extreme state of matter intermediate-between-condensed mattor and adoal plasma, widely within celestial bodies in the universe and also a crucial stage in fusion processes. Its particle transport characteristics are key to understanding the structure and evolution laws of matter under extreme conditions, as well as important input parameters for inertial confinement fusion theoretical modeling and astrophysical models. Ion beam-driven warm dense matter possesses unique advantages, capable of generating warm dense matter with millimeter-scale spatial dimensions, uniform state, and durations on the order of hundreds of nanoseconds, providing significant opportunities for studying the fundamental physical properties of warm dense matter. This article briefly introduces the generation and evolution of warm dense matter driven by ion beams, as well as typical advances in ion transport properties and ionization radiation characteristics in dense plasma.

We present an experimental investigation into the radiative heating of boron-doped carbon-hydrogen-oxygen (CHO) foam targets by x-ray fluxes generated from laser-driven gold hohlraum. Time-integrated x-ray transmission and emission spectra were measured. The spectra exhibit a 26 eV blackbody radiation source background with a pronounced absorption profile and characteristic emission lines from the CHO plasma. The absorption profile roughly ranging from 8 to 13 nm arises from partially ionized carbon and oxygen ions. The plasma parameters, such as temperature, ionization degree, free electron density, coupling parameter, and degeneracy, were determined based on the characteristic emission lines intensity analysis. As the foam density increases, the x-ray absorption efficiency rises that is experimentally proved by the larger absorption profile, while the plasma electron temperature decreases, and the free electron density increases. The radiative heating mechanisms transferred from volumetric x-ray heating in an optically thin medium at low densities like 2

The transport of a laser-accelerated intense proton beam through a well-characterized dense plasma ( L similar to 1mm,T similar to 17eV,ne similar to 4x1020cm3) was experimentally studied. The plasma was produced by irradiating a foam target ( rho=2mgcm-3) with soft x-ray radiation from a laser-driven hohlraum. A symmetric setup allowed part of the proton bunch to propagate through the plasma, while the other part passed through an adjacent empty channel without target material. This enabled us to do in a single laser shot a comparison of the beam properties with and without plasma interaction while also mitigating shot-to-shot fluctuations. Measurements revealed a transformation of the initially flat beam profile into a halo structure after plasma traversal. Particle-in-cell simulations attribute this effect to magnetic fields generated at the plasma boundary, where the beam exhibits a sharp edge due to collimation by the target holder. These results constitute direct experimental evidence for self-modulation instability of an intense proton bunch in dense plasma. This work has implications for high-energy-density physics and fast ignition scenarios, where controlled proton beam transport in dense plasmas is critical. The presented method also provides a platform for systematic investigations of beam-plasma interactions across wider parameter ranges.

Investigating atomic processes and nuclear reactions in dense plasmas, and exploring the complex many-body correlationsamong particles in plasma environments, is fundamental to understanding basic physical processes in astrophysical andfusion plasmas. This paper summarizes key advances in atomic processes during the interaction between ion beams anddense plasmas. When carbon ions traverse a plasma with a density of 4 & times;10(20)/cm(3), the target-density effect increases themean charge state of the outgoing ions; dielectronic recombination reduces the charge-state distribution and shortens thecharge-equilibration time; collective effects induced by intense ion beams in dense plasmas enhance energy loss; and ionexcited states contribute significantly to beam energy deposition. The paper also reviews important achievements in plasmanuclear reactions: theoretical and experimental results on the electron-screening potential in plasmas remain discrepant;self-calibrated measurements of nuclear reaction cross sections can mitigate errors arising from plasma instabilities; proton-boron fusion yields in boron plasmas have been reported to increase by approximately two orders of magnitude; andmicrostructured targets are expected to further enhance the proton-boron fusion yield by about a factor of six

Ion stopping in dense plasma is crucial for stellar evolution and fusion ignition. However, its behavior in the strong ion-plasma coupling regime beyond the linear limit has long remained elusive, due to formidable experimental challenges. Here we report the first experimental investigation of ion stopping at an unprecedented coupling parameter exceeding unity, achieved by sending laser-accelerated short-pulse and intense quasi-monoenergetic carbon ions (∼583 keV/u, C^5+) into a uniform, long-lived, well-characterized dense plasma target (T_e ≈ 17 eV, n_e ≈ 4×10^20 cm^-3). By simultaneously measuring ion energy loss and charge-state evolution, we eliminated key experimental ambiguities arising from charge-state determination. Our results clearly show a reduction in stopping power compared with predictions from standard linear dielectric response or binary collision models, and they agree well with the hybrid calculation of molecular dynamics with quantum corrections. The importance of nonlinear screening effects arising from many-body interactions and quantum effects due to the wave nature of electrons was demonstrated at strong coupling. This work establishes a definitive high-fidelity experimental benchmark for collisional dynamics in the strong-coupling regime. It offers critical insight for accurate modeling of energy transport in inertial confinement fusion and astrophysical plasmas.

It has been previously advocated that the presence of the daily and annual modulations of the axion flux on the Earth's surface may dramatically change the strategy of the axion searches. The arguments were based on the so-called Axion Quark Nugget (AQN) dark matter model which was originally put forward to explain the similarity of the dark and visible cosmological matter densities Omega dark Omega visible. In this framework, the population of galactic axions with mass 10-6 eV ma 10-3 eV and velocity hvai 10-3c will be accompanied by axions with typical velocities hvai 0.6c emitted by AQNs. Furthermore, in this framework, it has also been argued that the AQN-induced axion daily modulation (in contrast with the conventional weakly interactive massive particle paradigm) could be as large as (10-20)%, representing the main motivation for the present investigation. We argue that the daily modulations along with the broadband detection strategy can be very useful tools for the discovery of such relativistic axions. The data from the CAST-CAPP detector have been used following such arguments. Unfortunately, due to the dependence of the amplifier chain on temperature-dependent gain drifts and other factors, we could not conclusively show the presence or absence of a dark sector-originated daily modulation. However, this proof of principle analysis procedure can serve as a reference for future studies.

The proton-boron B-11(p, alpha) 2 alpha reaction (p-B-11) is an interesting alternative to the D-T reaction for fusion energy, since the primary reaction channel is aneutronic and all reaction partners are stable isotopes. We measured the alpha production yield using protons in the 120-260 keV energy range impinging onto a hydrogen-boron-mixed target, and for the first time present experimental evidence of an increase of alpha-particle yield relative to a pure boron target. The measured enhancement factor is approximately 30%. The experiment results indicate a higher reactivity, and that may lower the condition for p-B-11 fusion ignition.

The equilibrium charge state distribution of laser -accelerated carbon ions traversing a tri-cellulose-acetate (TCA, C 9 H 16 O 8 ) foam target was measured experimentally. The ions were generated through the target normal sheath acceleration mechanism. This allowed us to obtain the equilibrium charge state for a wide energy range near the maximum energy loss within a single laser shot. The foam had a porous structure with 2 mg / cm 3 volume density, which is between the typical density of gas- and solid-state matter. We found that the measured average equilibrium charge states were significantly underestimated by theoretical models applicable for gas targets, while were in close agreement with both semiempirical formulas and rate equation predictions based on ion -solid interactions. The solid -density fiber filaments in the current foam structure were attributed and demonstrated. The target density effects, which increase the ionization probability through frequent collisions and decrease the electron capture probability, were proven to play an important role in the foam target. Since the foam targets are widely used in laser plasma interaction experiments, our findings are relevant for a broad range of applications.

A novel intense beam-driven scheme for high yield of the tri-alpha reaction 11B(p,{\alpha})2{\alpha} was investigated. We used a foam target made of cellulose triacetate (TAC, C_9H_{16}O_8) doped with boron. It was then heated volumetrically by soft X-ray radiation from a laser heated hohlraum and turned into a homogenous, and long living plasma. We employed a picosecond laser pulse to generate a high-intensity energetic proton beam via the well-known Target Normal Sheath Acceleration (TNSA) mechanism. We observed up to 10^{10}/sr {\alpha} particles per laser shot. This constitutes presently the highest yield value normalized to the laser energy on target. The measured fusion yield per proton exceeds the classical expectation of beam-target reactions by up to four orders of magnitude under high proton intensities. This enhancement is attributed to the strong electric fields and nonequilibrium thermonuclear fusion reactions as a result of the new method. Our approach shows opportunities to pursue ignition of aneutronic fusion.

We report on charge state measurements of laser-accelerated carbon ions in the energy range of several MeV penetrating a dense partially ionized plasma. The plasma was generated by irradiation of a foam target with laser-induced hohlraum radiation in the soft x-ray regime. We use the tricellulose acetate (C_{9}H_{16}O_{8}) foam of 2  mg/cm^{3} density and 1 mm interaction length as target material. This kind of plasma is advantageous for high-precision measurements, due to good uniformity and long lifetime compared to the ion pulse length and the interaction duration. We diagnose the plasma parameters to be T_{e}=17  eV and n_{e}=4×10^{20}  cm^{-3}. We observe the average charge states passing through the plasma to be higher than those predicted by the commonly used semiempirical formula. Through solving the rate equations, we attribute the enhancement to the target density effects, which will increase the ionization rates on one hand and reduce the electron capture rates on the other hand. The underlying physics is actually the balancing of the lifetime of excited states versus the collisional frequency. In previous measurement with partially ionized plasma from gas discharge and z pinch to laser direct irradiation, no target density effects were ever demonstrated. For the first time, we are able to experimentally prove that target density effects start to play a significant role in plasma near the critical density of Nd-glass laser radiation. The finding is important for heavy ion beam driven high-energy-density physics and fast ignitions. The method provides a new approach to precisely address the beam-plasma interaction issues with high-intensity short-pulse lasers in dense plasma regimes.

The charge equilibration of laser-accelerated carbon ion beams in 2 mg/cm3 foam target was investigated experimentally. The ions were generated through target normal sheath acceleration mechanism in laser-foil interaction scheme. This allows to get the equilibrium charge state in wide energy range near Bragg peak within a single shot. By using foam, the charge equilibration measurement in density regime between gas and solid state was firstly reached out experimentally. It was found that the theoretical predictions with tabulated cross section data for gas target greatly underestimated the charge states. The experimental data are in close agreement with both semi-empirical formula as well as rate equation predictions based on ion-solid interactions. The important role of target density effects that increase the ionization probability and decrease the electron capture probability through frequent multi-collisions in foam are demonstrated. The double electron processes are shown to have little influence on the average charge states. The findings are essential for high energy density physics research where the foams are widely used, and have impacts on a broad range of applications in medical, biological and material fields. The method also provides a new approach to investigate the interaction mechanism of swift heavy ions in matter by taking advantage of the laser-accelerated short-pulse wide-energy range ions.

We compare the transport properties of a well-characterized hydrogen plasma for low and high current ion beams. The energy-loss of low current beams can be well understood, within the framework of current stopping power models. However, for high current proton beams, significant energy-loss reduction and collimation is observed in the experiment. We have developed a new particle-in-cell code, which includes both collective electromagnetic effects and collisional interactions. Our simulations indicate that resistive magnetic fields, induced by the transport of an intense proton beam, act to collimate the proton beam and simultaneously deplete the local plasma density along the beam path. This in turn causes the energy-loss reduction detected in the experiment.

The proton drip-line nucleus 17Ne is investigated experimentally in order to determine its two-proton halo character. A fully exclusive measurement of the 17Ne(p,2p)16F→15⁎O+p quasi-free one-proton knockout reaction has been performed at GSI at around 500 MeV/nucleon beam energy. All particles resulting from the scattering process have been detected. The relevant reconstructed quantities are the angles of the two protons scattered in quasi-elastic kinematics, the decay of 16F into 15O (including γ decays from excited states) and a proton, as well as the 15O+p relative-energy spectrum and the 16F momentum distributions. The latter two quantities allow an independent and consistent determination of the fractions of l=0 and l=2 motion of the valence protons in 17Ne. With a resulting relatively small l=0 component of only around 35(3)%, it is concluded that 17Ne exhibits a rather modest halo character only. The quantitative agreement of the two values deduced from the energy spectrum and the momentum distributions supports the theoretical treatment of the calculation of momentum distributions after quasi-free knockout reactions at high energies by taking into account distortions based on the Glauber theory. Moreover, the experimental data allow the separation of valence-proton knockout and knockout from the 15O core. The latter process contributes with 11.8(3.1) mb around 40% to the total proton-knockout cross section of 30.3(2.3) mb, which explains previously reported contradicting conclusions derived from inclusive cross sections.

The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole magnet, has searched for axions in the 19.74 μ eV to 22.47 μ eV mass range. The detection concept follows the Sikivie haloscope principle, where Dark Matter axions convert into photons within a resonator immersed in a magnetic field. The CAST-CAPP resonator is an array of four individual rectangular cavities inserted in a strong dipole magnet, phase-matched to maximize the detection sensitivity. Here we report on the data acquired for 4124 h from 2019 to 2021. Each cavity is equipped with a fast frequency tuning mechanism of 10 MHz/ min between 4.774 GHz and 5.434 GHz. In the present work, we exclude axion-photon couplings for virialized galactic axions down to g a γ γ = 8 × 10 −14 GeV −1 at the 90% confidence level. The here implemented phase-matching technique also allows for future large-scale upgrades.

High-energy-density physics (HEDP) deals with the study of matter under extreme conditions with an energy density higher than 10(11) J/m(3), corresponding to a pressure of 100 GPa. Such matter exists in abundance in deep interiors of the planets and stars. It also exists for a short duration during nuclear explosion and the loading of high-power-pulsed machines. HEDP is the international frontier of national security, astrophysics and fusion science, and it is also one of the main scientific goals of the high-power laser-facilities, Z-machines and heavy-ion-accelerators. Herein, the HEDP research based on High Intensity heavy-ion Accelerator Facility (HIAF), which is the "12th Five-Year Plan" national major science and technology infrastructure, will be introduced. The HIAF is advocated to provide the world with a heavy-ion beam with utmost high power. The energy and power of one beam pulse is about 100 J and several TW, respectively. With such a high-power heavy-ion beam, heating a solid-state lead sample, for example, could generate homogenous high-energy-density matter with a spatial scale from mm to cm and a temperature of 10 eV, near-solid density, and energy density of 10(13) J/m(3). Thus, through the HIAF, the generation, properties and evolution of highenergy-density matter can be investigated. This paper also reports the state of the art in the field of HEDP based on HIAF, including the generation and development of high-energy-density matter driven by a high-intensity heavy-ion beam, micro mechanism of interaction between the ion beam and dense matter or plasma, and key diagnostics of the highenergy-density matter driven by a hevy-ion beam.

Heavy ion inertial fusion (HIF) energy would be one of promising energy resources securing our future energy in order to sustain our human life for centuries and beyond. The heavy ion beam (HIB) has remarkable preferable features to release the fusion energy in inertial confinement fusion: in particle accelerators HIBs are generated with a high driver efficiency of   30-40 requirement for the fusion target energy gain is relatively low, that would be  50-70 to operate a HIF fusion reactor with the standard energy output of 1GW of electricity. The HIF reactor operation frequency would be  10 15 Hz or so. Several-MJ HIBs illuminate a fusion fuel target, and the fuel target is imploded to about a thousand times of the solid density. Then the DT fuel is ignited and burned. The HIB ion deposition range would be  0.5-1 mm or so depending on the material. Therefore, a relatively large density-scale length appears in the fuel target material. The large density-gradient-scale length helps to reduce the Rayleigh-Taylor (R-T) growth rate. The key merits in HIF physics are presented in the article toward our bright future energy resource.