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Field Line Resonances (FLRs) are a critical component in Earth's magnetospheric dynamics, associated with the transfer of energy between Ultra Low Frequency waves and local plasma populations. In this study we investigate how the polarisation of FLRs are impacted by cold plasma density distributions during geomagnetic storms. We present an analysis of Van Allen Probe A observations, where the spacecraft traversed a storm time plasmaspheric plume. We show that the polarisation of the FLR is significantly altered at the sharp azimuthal density gradient of the plume boundary, where the polarisation is intermediate with significant poloidal and toroidal components. These signatures are consistent with magnetohydrodynamic modeling results, providing the first observational evidence of a 3D FLR associated with a plume in Earth's magnetosphere. These results demonstrate the importance of cold plasma in controlling wave dynamics in the magnetosphere, and have important implications for wave‐particle interactions at a range of energies. Plain Language Summary: Earth's space environment is home to electrons and ions across a wide range of energies, trapped in the region by our global geomagnetic field. Energy can be transferred to and from the trapped particles through oscillations in the magnetic field, and these processes are responsible for the extreme energization of trapped electrons to hazardous levels for local spacecraft. In this paper we explore a type of magnetic field oscillation termed Field Line Resonances (FLRs): standing waves on a field line analogous to the oscillatory motion of guitar strings. We use spacecraft observations to show that the direction of the field line oscillations changes significantly depending on the density of the background plasma. The results confirm previous modeling work, and are the first observational evidence of 3D FLRs at a plume. The findings have important consequences for how FLRs transfer energy between the electrons and ions. Key Points: We present the first observational evidence of a 3D Field Line Resonance at the sharp density gradient of a plume edgeThe observed polarisation change confirms magnetohydrodynamic modeling results and predictions made by Elsden and Wright (2022)The presence of 3D Field Line Resonances during storm times has impacts for how Ultra Low Frequency waves couple and interact with local plasma [ABSTRACT FROM AUTHOR]

Gray mold caused by Botrytis cinerea is a serious disease of grape (Vitis vinifera) during storage. The aim of this study is to evaluate the effect of atmosphere cold plasma (a novel and nonthermal technology) on inactivation of B. cinerea and preservation of chemical, physical, and mechanical characteristics of grape inoculated with B. cinerea. Herein, different time of cold plasma (0, 10, 20, and 40 s) was firstly considered to be the main factors, besides different storage time (1, 2, 3, 4, and 5 weeks) at 4°C. According to the results, plasma treatment exhibited inhibitory effect on gray mold percentage and microbial load of B. cinerea (log CFU g−1) during postharvest storage. So, in the last week, the gray mold percentage and microbial load in the control were 100% and 3.6 log CFU g−1, and in 40‐s plasma were 4.5% and 2.53 log CFU g−1, respectively. Although the minimum infection and microbial load were observed in 40‐s plasma, better postharvest quality preservation was observed in short‐time cold plasma treatment (≤20 s). Forty‐second plasma caused fruit tissue destruction and negatively decreased mechanical indices (Emod: 0.0028, Fmax = 1.78, and W = 3.18) and weight loss (91.9) in comparison with ≤20‐s plasma, in which mechanical indices (Emod =0.0077, Fmax = 3.6, and W = 10.06) and weight loss (1/1) were higher. The long‐time cold plasma treatment (40 s) had also maximum effects on color changes (10) and surface temperature (2.8°C). Although the highest TSS and TA were observed in 40‐s Plasma, but different time of plasma treatments had no effect on pH. Altogether, these results indicate that the short‐time cold plasma treatment can inactivate B. cinerea on grape berries and preserve crop quality properties. [ABSTRACT FROM AUTHOR]

One of the nonthermal methods is the atmospheric pressure cold plasma (APCP). In this study, the effect of cold plasma on the reduction of Escherichia coli bacteria and qualitative properties of sour cherry juice, including total phenolic content (TPC), total anthocyanin content (TAC), and vitamin C, were investigated. Independent variables included plasma exposure time (1, 5, and 9 min), applied field intensity (25, 37.5, and 50 kV/cm), feeding gas oxygen content (0%, 0.5%, and 1%), and sample depth (0.5, 1, and 1.5 cm). The results show that increased oxygen content in argon has the greatest effect on the reduction of bacteria, and plasma exposure decreased 6 logarithmic periods of E. coli bacteria in sour cherry juice. Optimization results showed when all bacteria were eliminated by plasma, TPC remained unchanged, and TAC and vitamin C decreased by 4% and 21%, respectively, while thermal methods increased TPC by 23% and decreased TAC and vitamin C by 26% and 77%, respectively. These results indicate that, compared with conventional thermal methods, sour cherry juice pasteurization using APCP has little effect on the juice qualitative properties, and this method can serve as a suitable alternative to conventional thermal methods. [ABSTRACT FROM AUTHOR]

The dispersion relation for electromagnetic ion cyclotron (EMIC) waves is analyzed for a multi‐ion cold plasma. Several cases accounting for the relative contribution of the nitrogen (N+) and the oxygen (O+) ions and wave normal angle (θ) are presented. It is found that the presence of N+ significantly changes the dispersion properties of EMIC waves, leading to a new frequency band with additional cutoff, crossover, and resonance frequencies just above the oxygen cyclotron frequency (ΩO+). The method for estimation of ions concentration from cutoff frequencies based on observation is also revisited, and N+ concentration is determined. The minimum resonant energy of N+ band is also calculated. This new N+ band is relevant to reduce the discrepancy in mode detection near ΩO+ in the observed wave spectrum in order to quantify the transport and energization of N+, in addition to O+, for their relative contribution to the loss and/or scattering mechanisms. Plain Language Summary: EMIC waves are important due to their role in the dynamics of the magnetosphere. The theoretical prediction of a new N+ band in EMIC waves has been proposed, which has totally different dispersion properties than O+ band and can lead to motivation for finding the possible solution to refine data of current missions with such mass resolution to distinct N+ from O+. The observational evidence of low‐frequency N+ band EMIC waves of this theoretical finding may become possible after the mass resolution. In this letter, we demonstrate that the relative contribution of N+ to O+ introduces a new N+ band and significantly affects the dispersion properties of EMIC waves. Key Points: Presence of N+ allows for the existence of a new N+ band close to ΩO+, which alters the dispersion characteristics of EMIC wavesN+ ion concentration is evaluated from the observed wave characteristics, which suggests almost the same N+ and O+ compositionThis new band has the potential to address the discrepancy between He+ and O+ bands near the ΩO+ and advance understanding of EMIC wave [ABSTRACT FROM AUTHOR]