390 research outputs found
Pure Just Tuning — Complete Harmonic Modulation with 8 Notes
No full textNote
This work is based on Reiji’s original ideas, verbal explanations, and handwritten notes in Japanese.
The English version has been translated by AI and organized by his guardian, with final approval from Reiji himself.
Abstract
This study proposes a novel theoretical approach to achieving a complete modulation system in pure just intonation using only eight notes.
Traditionally, just intonation provides exceptionally beautiful harmony within a single key, but suffers from pitch inconsistencies when modulating to other keys. This research introduces a unique method that combines progressions of perfect fifths and perfect fourths, enabling full key modulation while preserving pure just intonation.
The approach is designed using microtonal approximation, dimensional analysis, and frequency-space visualization, and is based on principles distinct from those of existing tuning systems such as Werckmeister III, Kirnberger III, Vallotti, and Young.
As a result, it theoretically achieves free modulation in pure just intonation—a capability that has long been considered impossible.
Authors: Reiji Konagaya (Primary Author), Nobuyuki Konagaya (Guardian, Co-author)
Update (v1.1):
Added a new figure, “Handwritten Diagram of Second Intervals in Pure Just Intonation,” illustrating the classification of second intervals (minor, neutral, and major) within the proposed tuning system. This addition enhances the visual explanation of the interval structure. No other changes were made to the main content.
Update (v1.2):
Added two new figures — “Handwritten Interval Map with Harmonic Ratios,” showing a sequential layout of pitches with their corresponding frequency ratios, and “Factorized Mathematical Representation of Tuning Ratios,” presenting each note’s ratio in multiple forms including prime factorization. These additions provide further clarity on both the musical and mathematical structure of the proposed tuning system. No other changes were made to the main content.
Update (v1.3):
Added one new figure, “Handwritten Structural Diagram of Pure Just Tuning,” which illustrates how each pitch ratio is derived and interconnected. In addition, new explanatory text was added to the sections “Definitions used in this article,” “Examples,” and “Fifths–Fourths relation,” further clarifying the theoretical framework of the system
Plasma physics and control studies planned in JT-60SA for ITER and DEMO operations and risk mitigation
No full textAlarge superconducting machine, JT-60SA has been constructed to provide major contributions to the ITER program and DEMO design. For the success of the ITER project and fusion reactor, understanding and development of plasma controllability in ITER and DEMO relevant higher beta regimes are essential. JT-60SA has focused the program on the plasma controllability for scenario development and risk mitigation in ITER as well as on investigating DEMO relevant regimes. This paper summarizes the high research priorities and strategy for the JT-60SA project. Recent works on simulation studies to prepare the plasma physics and control experiments are presented, such as plasma breakdown and equilibrium controls, hybrid and steady-state scenario development, and risk mitigation techniques. Contributions of JT-60SA to ITER and DEMOhave been clarified through those studies.Peer ReviewedArticle escrit per 127 autors/autores:
M Yoshida, G Giruzzi, N Aiba, J F Artaud, J Ayllon-Guerola, L Balbinot, OBeeke, E Belonohy, P Bettini, W Bin, A Bierwage, T Bolzonella, M Bonotto, CBoulbe, J Buermans, M Chernyshova, S Coda, R Coelho, S Davis, C Day, GDeTommasi, M Dibon, A Ejiri, G Falchetto, A Fassina, B Faugeras, L Figini, M Fukumoto, S Futatani, K Galazka, J Garcia, M Garcia-Muñoz, L Garzotti, L Giacomelli, L Giudicotti, S Hall, N Hayashi, C Hoa, M Honda, K Hoshino, M Iafrati, A Iantchenko, S Ide, S Iio, R Imazawa, S Inoue, A Isayama, E Joffrin, K Kamiya, Y Ko, M Kobayashi, T Kobayashi, G Kocsis, A Kovacsik, T Kurki-Suonio, B Lacroix, P Lang, Ph Lauber, A Louzguiti, E de la Luna, G Marchiori, M Mattei, A Matsuyama, S Mazzi, A Mele, F Michel, Y Miyata, J Morales, P Moreau, A Moro, T Nakano, M Nakata, E Narita, R Neu, S Nicollet, M Nocente, S Nowak, F P Orsitto, V Ostuni, Y Ohtani, N Oyama, R Pasqualotto, B Pégourié, E Perelli, L Pigatto, C Piccinni, A Pironti, P Platania, B Ploeckl, D Ricci, P Roussel, G Rubino, R Sano, K Särkimäki, K Shinohara, S Soare, C Sozzi, S Sumida, T Suzuki, Y Suzuki, T Szabolics, T Szepesi, Y Takase, M Takech, N Tamura, K Tanaka, H Tanaka, M Tardocchi, A Terakado, H Tojo, T Tokuzawa, A Torre, N Tsujii, H Tsutsui, Y Ueda, H Urano, M Valisa, M Vallar, J Vega, F Villone, T Wakatsuki, T Wauters, M Wischmeier, S Yamoto, L ZaniPostprint (published version
Development of pulsed plasma operation scenario and required conditions in JA DEMO
No full textWe have developed the pulsed plasma operation scenarios for JA DEMO, a design concept of the steady-state tokamak demonstration reactor, to clarify controls of the current profile and power required for the operation. We compare the scenarios when injecting electron cyclotron waves only and both neutral beam and electron cyclotron waves for external heating and current drive. We demonstrate current profile control that maintains the minimum value of the safety factor above one and avoids creating the local minima in the safety factor profile and power control by argon seeding that maintains the fusion power constant at the desired value and reduces the heat load on the divertor, performing long-time integrated modeling simulations. We clarify the conditions of the heating and current drive system and impurity injection system required for such control. The dependence of power control on argon anomalous transport coefficients is investigated. We have the prospect of maintaining the fusion power of 1 GW for more than two hours, i.e. obtaining the required plasma performance determined using a systems code.journal articl
High ion-exchange properties of hybrid materials from X-type zeolite and ground glass powder
No full textParameter study of L-H transition for plasma operation scenario development in JA DEMO
No full textWe have investigated the L?H transition in JA DEMO, a design concept of the steady-state tokamak fusion demonstration reactor. We develop an L?H transition model, which determines the minimum pedestal growth time such that a power ratio, the net plasma loss power across the separatrix over the L?H threshold power, is maintained at a constant value during pedestal growth for a given external heating power. We conduct parameter studies using an integrated modeling code, considering impurity transport. The dependence of the heating power and time required for the L?H transition on the plasma density, temperature, threshold power, impurity density fraction, and impurity transport coefficients is clarified. We evaluate the appropriate impurity density fraction for the L?H transition and the divertor heat load reduction. The fraction depends on the impurity transport coefficients and external heating power. The obtained results are necessary to confirm the L?H transition feasibility and to develop the plasma operation scenario consistent with the various engineering constraints in a design-stage reactor. The heating power required for the L?H transition turns out to be lower than the power supposed to be installable in the current design activities of JA DEMO.journal articl
Free-boundary stability analysis of tokamak plasmas by ERMHDT
No full textWe have developed an eigenvalue code ERMHDT forresistive magnetohydrodynamics (MHD) linear stabilityanalysis of tokamak plasmas including toroidal rotations.The code has been recently upgraded for free-boundarycalculations. We have achieved good agreements of idealMHD growth rates with other existing codes for Solov ́evequilibria. Also we have successfully captured thatfree-boundary ideal kink modes and fixed-boundary tear-ing modes are smoothly connected by the free-boundaryresistive MHD stability analysis.3rd Asia-Pacific Conference on Plasma Physicsconference objec
MUSES: A nonlinear magnetohydrodynamics discontinuous Galerkin code for fusion plasmas
No full textThe article describes initial steps toward the development of our nonlinear magnetohydrodynamics code, MUSES. Unstructured grids and general coordinates are employed so that MUSES code is expected to have a capability to represent realistic geometries of fusion devices. Discontinuous Galerkin method is chosen as a code framework because of its high spatial accuracy and numerical stability on unstructured grids. The governing equation of the ideal magnetohydrodynamics in this work is Powell 8-wave model which can mitigate the divergence-free issue. Roe scheme is used as a numerical flux since the Powell 8-wave model is a nonconservative system. A cross code comparison is carried out with a linear magnetohydrodynamics code, MINERVA. Owing to discontinuous Galerkin method, a linear theory of an ideal internal kink mode is reproduced quantitatively although the upwind method is employed for numerical stability
- …
