Current Status of Railgun Research

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(1) Stew Magnuson, Japan Looks to Partner with U.S. on Railgun Project. National Defense Magazine, Apr 17, 2023
https://www.nationaldefensemagaz ... -on-railgun-project
("technical hurdles concerning the overheating of the railgun couldn't be overcome * * * Two of the main issues with the technology's development are the energy required and the heat generated * * * And the power [of railgun] has to go somewhere — much of it to heating — which means the structure can get very hot")

Note:
(a)
(i) Stew Magnuson is editor in chief of the Magazine. His birth name is Stewart. Stu is short for Stuart.
(ii) Stewart (name)
https://en.wikipedia.org/wiki/Stewart_(name)
is Scottish spelling and Stuart is French spelling.

(b) "Shigenori Mishima, vice commissioner and chief technology officer at the Japanese Ministry of Defense's Acquisition, Technology and Logistics Agency, listed a railgun as one of the military’s top research and development priorities at the DSEI Japan conference recently."
(i)
(A) Shigenori MISHIMA  三島 茂徳  (Compare Shiheru YOSHIDA (prime minister 1948-1954); The verb shigeru 茂る simply means "plants grow thickly.")
chief technology officer (more apt translation is Chief Defense Scientist)  防衛技監  (Breen dictionary: gikan 技監 【ぎかん】 (n): "engineer-in-chief; chief engineer; chief scientist")
(B) He earned PhD from MIT in 1996 (So his education 学歴 in Japanese: 昭和63年東大大学院 [MS]。平成8年マサチューセッツ [katakana for Massachusetts] 工科大学大学院。 Breen dictionary: da-i-gaku-en 大学院 【だいがくいん】 (n): "graduate school"

Shigeru Mishima, Design of Cavitating Propeller Blades in Non-Uniform Flow by Numerical Optimization. Department of Ocean Engineering, MIT, September 1996.
https://dspace.mit.edu/bitstream ... 06/36830035-MIT.pdf
(ii) Ministry of Defense (MOD)  防衛省
(iii) Acquisition, Technology and Logistics Agency (ATLA)  防衛装備庁 (pronunciation: bōei sōbi-chō; established in 2015 by Abe Administration; "防衛省の外局": ja.wikipedia.org; its head is 長官 (which is obviously translated as Commissioner; officially there is no Deputy Commissioner in this Agency)
(A) What does 外局 mean?

A general Japanese-English dictionary (online; compiled by Jim Breen of Australia) shows:
* shi-ga-i-kyoku-ban 市外局番 【しがいきょくばん】 (n): "(telephone) area code (non-local)"  (The 番 is short for 番号 -- pronunciation bango -- telephone number.)
* sh0-na-i-kyoku-ban 市内局番 【しないきょくばん】 (n): "local telephone exchange number"
(B) 防衛省
https://ja.wikipedia.org/wiki/防衛省
, whose table demonstrates, in a nutshell, the structures:
"上部組織        内閣
内部部局        大臣官房 [pronunciation: kanbō; government secretariat] and many others.
* * *
地方支分部局        地方防衛局
外局        防衛装備庁")

In other words, 外局 is in contrast to 地方支分部局.
(iv) DESI
https://en.wikipedia.org/wiki/DSEI
is held in London every other year. DESI Japan is held in City of Chiba, Chiba Prefecture in the same time by in Japan. That is why this article is dispatched from Chiba (see the first word of the article.

Chiba (city)
https://en.wikipedia.org/wiki/Chiba_(city)
("It sits about 40 kilometres (25 mi) [air distance] east of the centre of Tokyo on Tokyo Bay")

(c) "The upper limit for conventional projectiles using propellants is about Mach 4.  'Since a railgun uses electromagnetic forces for propulsion [and does not use propellant], there's no detonation speed limit, so hypersonic speeds can theoretically be achieved,' he said."
(i) ramjet
https://en.wikipedia.org/wiki/Ramjet
(the last paragraph of introduction starts with "As speed increases, the efficiency of a ramjet starts to drop")
(ii) Meteor (missile)
https://en.wikipedia.org/wiki/Meteor_(missile)
("A solid-fueled ramjet motor allows the missile to cruise at a speed of over Mach 4"/ table: Place of origin         Europe (multinational), In service  since 2016, Manufacturer        MBDA)


(2) Inder Singh Bisht, Japan Considers US Partnership on Railgun Project: Report. The Defense Report, Apr 27, 2023.
https://www.thedefensepost.com/2 ... us-railgun-project/

Quote:

"BAE worked on a US Navy railgun project as a prime contractor while General Atomics clinched a three-year-long US Army railgun project in 2018.   BAE developed a 32-megajoule railgun in a laboratory setting that could fire a projectile 220 miles at Mach 7.5. * * * Similarly, General Atomics delivered a 10-megajoule railgun prototype to strike over 60 miles (96 kilometers) away, but the project ended in 2021.

"However, there is a question mark over the railgun's viability, as it requires significant power to operate. Secondly, the power generates a lot of heat, which makes the system too hot to operate.   'Railguns operate by exerting extreme electromagnetic forces on a projectile, but those forces act against the railgun structure itself. This means they tend to self-destruct,' the National Defense Industrial Association’s Emerging Technologies Institute Mark Lewis said.

Note: The "Report" in the title is the Magazine in (1). There is no need to read except the quotations above.